Pennock's Fiero Forum
  Technical Discussion & Questions
  using relays in place of the headlight motor control module

Post New Topic  Post A Reply
Email This Page to Someone! | Printable Version


next newest topic | next oldest topic
using relays in place of the headlight motor control module by qwikgta
Started on: 01-12-2020 07:40 PM
Replies: 18 (384 views)
Last post by: donuteater306 on 02-09-2020 07:04 PM
qwikgta
Member
Posts: 4380
From: Virginia Beach, VA
Registered: Jan 2001


Feedback score:    (21)
Leave feedback





Total ratings: 83
Rate this member

Report this Post01-12-2020 07:40 PM Click Here to See the Profile for qwikgtaClick Here to Email qwikgtaSend a Private Message to qwikgtaEdit/Delete MessageReply w/QuoteDirect Link to This Post
OK, so i have used the search and found some data that is close to what I'm looking to do but here is the issue. The other day my headlight motors stopped working. I checked the motors using a 12V source and they go up and down just fine, nothing interfering with their movement. I have checked the switch and its also good. I have 12V at the switch, and the lights work just fine. I'm 100% sure its the control module. I realize they are easy to swap out but hard to find, even if you find one used, it may be bad. So looking at the wiring diagram in the 88 manual it seems that I could just run a set of 5 wire relays up, power to both sides w/ a switch that stays in a neutral position so no power will be lost.

In my thinking it would work just like power windows, you push the button "up" for the motors to have power and go "up". when they are up you let go of the button. Same thing for going down. Again, its just like power windows. Button in the neutral posit would not do anything and there would not be a power drain.

I know it would require another switch, but I have a blank spot under the power trunk lock switch, so putting a button on the dash is no issue. The old light switch will just be used for turning on the lights.

This is the diagram I came up with (with help from the internet)



Thanks in advance.

Rob

[This message has been edited by qwikgta (edited 02-05-2020).]

IP: Logged
PFF
System Bot
theogre
Member
Posts: 28696
From: USA
Registered: Mar 99


Feedback score: N/A
Leave feedback





Total ratings: 547
Rate this member

Report this Post01-13-2020 12:30 AM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
See my Cave, Gen 2 HL Motor

Any Manual method to "replace" the module is a bad idea.
Motors have "Shear pins" to break for overloaded for jams, End of Travel, etc. and more so if module has problems covered in cave etc.
This pins die for that and old age.
If you or anyone put aftermarket Delrin pins in them then often just a matter of time the gears etc break because they are the weak part now. That before adding switches relays or whatever. see http://www.fiero.nl/forum/Forum2/HTML/128600.html

Module sees jam/EoT loads and kill power to the motors in microseconds.
You only turn off in 1-2 seconds and "beats up" the motors and rest of HL lifts electrically and mechanically every time you do.
Motors running only uses 3 to 4 amps max. Unmanaged stall can draw 3x to 5x that and burns out the motor.

"Bad" module can be a lot of issues.
Iffy wiring to it is a big one.
Crack solder at big pins on the board that wire plugs into is another. Reflowing solder there needs 25w at bare minimum, high gun/iron is better to heat fast w/o damage the board. Rest of board needs 25w iron or less because most joists are very small.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)


The Ogre's Fiero Cave

IP: Logged
FX
Member
Posts: 216
From:
Registered: Apr 2018


Feedback score: N/A
Leave feedback

Rate this member

Report this Post01-13-2020 10:35 AM Click Here to See the Profile for FXClick Here to Email FXSend a Private Message to FXEdit/Delete MessageReply w/QuoteDirect Link to This Post
If you're talking about the isolation relay as the 'control module', Rodney Dickman makes them up. I bought one for my 86 and it works as it should...
IP: Logged
olejoedad
Member
Posts: 13493
From: Clarendon Twp., MI
Registered: May 2004


Feedback score: (5)
Leave feedback





Total ratings: 184
Rate this member

Report this Post01-13-2020 11:39 AM Click Here to See the Profile for olejoedadClick Here to Email olejoedadSend a Private Message to olejoedadEdit/Delete MessageReply w/QuoteDirect Link to This Post
He has the Gen 2 headlights.....
IP: Logged
Larryinkc
Member
Posts: 413
From: Kansas City, MO USA
Registered: Nov 2012


Feedback score: (3)
Leave feedback

Rate this member

Report this Post01-13-2020 03:10 PM Click Here to See the Profile for LarryinkcSend a Private Message to LarryinkcEdit/Delete MessageReply w/QuoteDirect Link to This Post
I have an 88 also and so far my headlight module works. If it fails my plan is to buy one of the new repro modules for 88 to 96 Corvettes. They are part # 16523917 which is the superseded part # of the original Fiero part. They are available from several sources for around $160.00.
IP: Logged
qwikgta
Member
Posts: 4380
From: Virginia Beach, VA
Registered: Jan 2001


Feedback score:    (21)
Leave feedback





Total ratings: 83
Rate this member

Report this Post01-13-2020 07:00 PM Click Here to See the Profile for qwikgtaClick Here to Email qwikgtaSend a Private Message to qwikgtaEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Larryinkc:

I have an 88 also and so far my headlight module works. If it fails my plan is to buy one of the new repro modules for 88 to 96 Corvettes. They are part # 16523917 which is the superseded part # of the original Fiero part. They are available from several sources for around $160.00.


yea, thats the point, they are $160 bucks. I have the relays, the wiring, the switch and I'd like to drive the car w/ out having the lights up all the time. If I can just wire up some relays and add a switch to the dash ... done. Plus if the damn things goes south again, i'm out another $160 bucks.

So i guess no input on the wiring part. I'll just wire it up and give it a try.

Rob
IP: Logged
theogre
Member
Posts: 28696
From: USA
Registered: Mar 99


Feedback score: N/A
Leave feedback





Total ratings: 547
Rate this member

Report this Post01-13-2020 07:42 PM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Larryinkc:
I have an 88 also and so far my headlight module works. If it fails my plan is to buy one of the new repro modules for 88 to 96 Corvettes. They are part # 16523917 which is the superseded part # of the original Fiero part. They are available from several sources for around $160.00.
Quick search GM list them as fitting Fiero and others...
just 1 Example: https://www.gmpartsgiant.co...module-16523917.html

Can find on Ebay, Eckler’s, etc for less money but even many GM parts dealers are Far less then TFS prices.

[This message has been edited by theogre (edited 01-13-2020).]

IP: Logged
qwikgta
Member
Posts: 4380
From: Virginia Beach, VA
Registered: Jan 2001


Feedback score:    (21)
Leave feedback





Total ratings: 83
Rate this member

Report this Post02-05-2020 07:00 PM Click Here to See the Profile for qwikgtaClick Here to Email qwikgtaSend a Private Message to qwikgtaEdit/Delete MessageReply w/QuoteDirect Link to This Post
For all who find this post, use the diagram above if you want to do this, i've added the second motor and updated the diagram. Green/Green together, and Gray/Gray together. I used a 5 pin power window switch from a Saturn (I liked the look over stock Fiero/Firebird style). The important part of the diagram is ground at 87A. I tried wiring it up a different way, and it would not work. The motors have to have one wire hot, the other ground to work. Wired up this way, 87A will remain grounded until the relay is energized which will allow power to travel from 87 to 30. Other side stay grounded.

On the dash, I removed the dimmer wheel, and pushed into the dash (i don't use it anyway) and cut a hole to fit the power window switch into it.

One switch opens/closes the headlights and the stock light switch turns them on/off.

Cost: $0 I had the two relay's, the wiring and the power window switch.
Save: $160 -$300 cost of a replacement module.

Cheers

Rob

[This message has been edited by qwikgta (edited 02-08-2020).]

IP: Logged
Dennis LaGrua
Member
Posts: 13078
From: Hillsborough, NJ U.S.A.
Registered: May 2000


Feedback score:    (11)
Leave feedback





Total ratings: 316
Rate this member

Report this Post02-05-2020 07:08 PM Click Here to See the Profile for Dennis LaGruaClick Here to Email Dennis LaGruaSend a Private Message to Dennis LaGruaEdit/Delete MessageReply w/QuoteDirect Link to This Post
I believe that the OEM headlight motor module has a safety feature that either reverses or kills the circuit if it is overloaded by a motor jam. The electro-mechanical method with the relays does not offer any such thing.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

IP: Logged
qwikgta
Member
Posts: 4380
From: Virginia Beach, VA
Registered: Jan 2001


Feedback score:    (21)
Leave feedback





Total ratings: 83
Rate this member

Report this Post02-05-2020 07:47 PM Click Here to See the Profile for qwikgtaClick Here to Email qwikgtaSend a Private Message to qwikgtaEdit/Delete MessageReply w/QuoteDirect Link to This Post
OK, so what. I mean i'm sitting right there in the drivers seat. I need lights so I open the doors. They open. Then I put on the lights. If I was using the stock module and I went to open them and there was a "Jam", they would not open. If I hit the button and they don't open, they don't open and I stop pressing the button. I don't get why everyone is so negative to saving $300 bucks. I get that if your stock module works you don't need to do this, but if your module goes out, this is something you can do. Thats all. I get that its not the way PONTIAC designed it. The stock module is just a super smart relay. Look at the wire diagram, its just a relay with some smart stuff built in. This is just another way to do it, thats all.

Rob
IP: Logged
fierosound
Member
Posts: 13992
From: Calgary, Canada
Registered: Nov 1999


Feedback score: N/A
Leave feedback





Total ratings: 277
Rate this member

Report this Post02-06-2020 12:04 PM Click Here to See the Profile for fierosoundClick Here to visit fierosound's HomePageClick Here to Email fierosoundSend a Private Message to fierosoundEdit/Delete MessageReply w/QuoteDirect Link to This Post
Rob... good fix.

Let us know if there's any problems down the road.
You're the guinea pig and Beta Tester.

[This message has been edited by fierosound (edited 02-06-2020).]

IP: Logged
PFF
System Bot
Mickey_Moose
Member
Posts: 7267
From: Edmonton, AB, Canada
Registered: May 2001


Feedback score: (3)
Leave feedback





Total ratings: 142
Rate this member

Report this Post02-06-2020 02:13 PM Click Here to See the Profile for Mickey_MooseClick Here to visit Mickey_Moose's HomePageClick Here to Email Mickey_MooseSend a Private Message to Mickey_MooseEdit/Delete MessageReply w/QuoteDirect Link to This Post
Brand new repro headlight modules - and - NO they are not $300: https://www.corvettepacific...dlamp-control-88-96/

or you can try here if you don't like that link.

https://www.corvettecentral...ontrol-module-445117

...of course you can do whatever you like, but, generally people with the 1st gen motors hate the relay system and wish they had the 2nd gen system. lol

[This message has been edited by Mickey_Moose (edited 02-06-2020).]

IP: Logged
theogre
Member
Posts: 28696
From: USA
Registered: Mar 99


Feedback score: N/A
Leave feedback





Total ratings: 547
Rate this member

Report this Post02-06-2020 05:30 PM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by fierosound:
Rob... good fix.

Let us know if there's any problems down the road.
You're the guinea pig and Beta Tester.
Not.
It will work but Is only a matter of time the motors break hitting EoT or jamming doing his way. Might take days to years depending on motors condition, how often used, and a lot more. Worse other will try too claiming that they work often to sell the car later to nubes think is normal .

Plus Manually control Gen2 motors w/ or w/o relay(s) can burn the contact close w/o warning then burn front wiring to the whole car because Doesn't even have limit switches and breaker built into Gen1 motors. Yes, they are Very crude but work well enough GM used that for 1 or 2 Decades before cost to make custom chips drop made Gen2 cheaper. (Likely same reason Lectron made GM "gen2" chime units w/ 1 custom chip about same time.) Relays in Gen1 setup mostly isolates power surges and amp draw to protect rest of car wiring.

Motors draw ~ 4a running... when stalled or switch(s) fried close will draw a lot more. The Fusible Links, B C & D, very likely Will Not blow before the motors and rest is melting or on fire. Cliff P burn out the "repaired" module and both motors and those links just laugh at the damage. He got lucky didn't burn the car and more.
If you install fuses then blows often or worse never causing same damage. How to you know? The module has 2 fuses marked F1 and F2 on the board and rarely blows when module fries like in same thread. Unlike a module given to me w/ a blown fuse after a front end wreck likely short out the wires to one motor. Wrong circuit breaker can to same thing and is only in Gen1 motors as backup for failed limit switch(es). (Failed limits are why Gen1 motor can kill the battery in hours. Breaker is auto reset w/ very short cycle timing.)

Motor die then what? If does have a fire when the motor die, He's likely to use Delrin pins etc. or replace w/ Cardone et al new ones that break again control by hand.
Having Delrin pins only guaranties you break the nylon gear or output shaft next time motor breaks. Finding a way to prop up a HL at night or bad weather is much worse then hand turning a motor to the up position. Far worse if you have health problems or on the highway.

Many can make "Arduino" MCU and some glue parts to do same job and w/ same features but not at ~ $150 for a complete unit sold at many "stores" like above.
Not even using china PC board makers to make enough money to have headache from fools think cost too much and other bs.
IP: Logged
qwikgta
Member
Posts: 4380
From: Virginia Beach, VA
Registered: Jan 2001


Feedback score:    (21)
Leave feedback





Total ratings: 83
Rate this member

Report this Post02-06-2020 06:25 PM Click Here to See the Profile for qwikgtaClick Here to Email qwikgtaSend a Private Message to qwikgtaEdit/Delete MessageReply w/QuoteDirect Link to This Post
You are really over thinking this. I push the up button and the headlights come up. I release the button when they are up. I turn on the light switch and lights come on. When I stop the car, I turn off the lights and then I push the down button and the headlights go down, I release the button when they are down.

Its not rocket science and your comments assume I am some kind of ****ing retard.

If the motors stop b/c something has gotten in the way, I would release the button, I would not keep it pressed down. Again, using common sense, you stop if something is wrong. I have to physically hold the button in either the up/down position for this to work, I can see the doors and hear the motors as they run.

Thank you for your input, and I believe you have made your point. We get it, you don't like to deviate from GM design, you never, ever have. Point made.

Thread ended.
IP: Logged
Sledgehammer
Member
Posts: 18
From: Scottsdale, AZ., USA
Registered: Aug 2019


Feedback score: N/A
Leave feedback

Rate this member

Report this Post02-06-2020 09:55 PM Click Here to See the Profile for SledgehammerSend a Private Message to SledgehammerEdit/Delete MessageReply w/QuoteDirect Link to This Post
I am glad you came up with an alternate solution for the headlight problem. I too suffered tracking down the problem . After rebuilding both headlight assemblies, replacing the switch, replaced the fusible links, I too even tested the headlights with a 12 volt battery and they worked fine. In my case only one headlight wouldn’t work. So I read through all the threads here and got some good ideas, I read the service manual test procedure for one headlight not functioning. Sooo., it appeared obvious by now that the problem was the infamous “control module”. I bit the bullet and bought one for $150. Now I was prepared to see the light (LOL) I removedf the inner wheel well and there she was it would only be a few minute now and I will see these lights work. Well as I removed the module and unplugged the connectssr there it was a “broken” gray wire on the connector. I repaired the wire and decided to try using the original old control module. Bang! they worked perfectly. After a few expletives and a hard glare at my newly acquired control module I started to wonderHow could that wire break in half like that. I mean where this module resides on the inner fender nothing could get to it to cut the wire. Well, low and behold if one looks at the outside trim on the fender which as we all know is fastened with two sheet metal screws. One of those screws is in a position not far from the control module connector. My signal light trim was broken when I got the car and I replaced it. So what happed I believe is that the left fender was hit or push inwards to where the sharp screw tip cut through the wire. I really didn’t have far to move to contact the wire and the fender being fiber glass bounced back with no damage. Incredible !! So I have an extra control module with the correct part number called for in the Service manual.
I guess the moral to the story is “ sometimes the simple obvious is to hard to see or believe”. Had I removed the old module before I bought the new one I would have seen the wire and fixed it and not had to resort to the foul abusive vocabulary needed to regain my patience.
IP: Logged
DavidM
Member
Posts: 73
From: Arlington TX USA
Registered: Oct 2009


Feedback score: N/A
Leave feedback

Rate this member

Report this Post02-07-2020 10:46 AM Click Here to See the Profile for DavidMClick Here to visit DavidM's HomePageClick Here to Email DavidMSend a Private Message to DavidMEdit/Delete MessageReply w/QuoteDirect Link to This Post
Personally, I like the relay solution - it gives back control and makes us less dependent on hard-to-find expensive GM parts.
Also, an over-current protection circuit & FET (ACS712 for example) would only add $2 or so. When mine fails - this is where I am going!

Let's encourage folks who come up with alternatives! (if they are relatively harmless)
IP: Logged
fierobear
Member
Posts: 26950
From: Stuck in the People's Republic of Kalifornia
Registered: Aug 2000


Feedback score: (2)
Leave feedback





Total ratings: 383
Rate this member

Report this Post02-07-2020 02:49 PM Click Here to See the Profile for fierobearClick Here to Email fierobearSend a Private Message to fierobearEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by theogre:

[QUOTE]Originally posted by Larryinkc:
I have an 88 also and so far my headlight module works. If it fails my plan is to buy one of the new repro modules for 88 to 96 Corvettes. They are part # 16523917 which is the superseded part # of the original Fiero part. They are available from several sources for around $160.00.
Quick search GM list them as fitting Fiero and others...
just 1 Example: https://www.gmpartsgiant.co...module-16523917.html

Can find on Ebay, Eckler’s, etc for less money but even many GM parts dealers are Far less then TFS prices.

[/QUOTE]

$367.68. Damn.
IP: Logged
fierosound
Member
Posts: 13992
From: Calgary, Canada
Registered: Nov 1999


Feedback score: N/A
Leave feedback





Total ratings: 277
Rate this member

Report this Post02-07-2020 05:54 PM Click Here to See the Profile for fierosoundClick Here to visit fierosound's HomePageClick Here to Email fierosoundSend a Private Message to fierosoundEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Mickey_Moose:

Brand new repro headlight modules - and - NO they are not $300:
https://www.corvettepacific...dlamp-control-88-96/



Different place, different price.
IP: Logged
donuteater306
Member
Posts: 581
From: San Francisco, CA USA
Registered: Feb 2010


Feedback score: N/A
Leave feedback

Rate this member

Report this Post02-09-2020 07:04 PM Click Here to See the Profile for donuteater306Click Here to Email donuteater306Send a Private Message to donuteater306Edit/Delete MessageReply w/QuoteDirect Link to This Post
Sometimes one or both of my headlamps wouldn't raise or lower. Open the module and float the solder on all the connections. Then check the relay contacts and clean if necessary. Doing so fixed mine. You have nothing to lose.
IP: Logged

next newest topic | next oldest topic

All times are ET (US)

Post New Topic  Post A Reply
Hop to:

Contact Us | Back To Main Page

Advertizing on PFF | Fiero Parts Vendors
PFF Merchandise | Fiero Gallery | Ogre's Cave
Real-Time Chat | Fiero Related Auctions on eBay



Copyright (c) 1999, C. Pennock