Pennock's Fiero Forum
  Technical Discussion & Questions
  Right head light goes up, Doesn't go down

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


next newest topic | next oldest topic
Right head light goes up, Doesn't go down by McCool
Started on: 04-14-2014 11:17 PM
Replies: 10 (295 views)
Last post by: Bloozberry on 04-24-2014 06:58 AM
McCool
Member
Posts: 302
From: Canada
Registered: Sep 2006


Feedback score: (1)
Leave feedback

Rate this member

Report this Post04-14-2014 11:17 PM Click Here to See the Profile for McCoolClick Here to Email McCoolSend a Private Message to McCoolEdit/Delete MessageReply w/QuoteDirect Link to This Post
Hey Guys,

I'm having trouble with my right headlight, It goes up just fine but won't go down. The left one functions normally.

I know the motor works before I hotwired to the wiring for the left side head light motor and it functions normally.

The problem seems to be with the the White/blue wire that comes from the iso relay because I am not getting any voltage from that wire where it connects to the headlight motor (when the headlight switch is off). I checked for voltage at the relay and I have none there (though I am assuming the middle prong in for the right headlight). When I check the prong right the left head light I am getting 12V out of the relay.

Does this mean my relay is busted? or does something happen before the relay that would only affect one headlight?

Thank You,
Greg McCool
IP: Logged
PFF
System Bot
Bloozberry
Member
Posts: 7760
From:
Registered: Jan 2009


Feedback score: N/A
Leave feedback





Total ratings: 307
Rate this member

Report this Post04-15-2014 07:48 AM Click Here to See the Profile for BloozberrySend a Private Message to BloozberryEdit/Delete MessageReply w/QuoteDirect Link to This Post
Here's how the power flows to the pod motors when you switch the headlights off:



If you're getting zero voltage on the iso relay where the blue/wht wire comes out, then your problem is the iso relay.

I doubt you'll be able to find an isolation relay to replace it though. Nobody (despite their claims) makes one, and used ones are like hens teeth. You can temporarily (or permanently) solve the problem by removing the relay and jumping the following wires together like so:

IP: Logged
joeschuit
Member
Posts: 56
From: Spring Lake, MI
Registered: Dec 2013


Feedback score: N/A
Leave feedback

Rate this member

Report this Post04-15-2014 08:23 AM Click Here to See the Profile for joeschuitClick Here to Email joeschuitSend a Private Message to joeschuitEdit/Delete MessageReply w/QuoteDirect Link to This Post
I had the opposite problem, they would both go down but one wouldn't go up. Try swapping the headlight relays that are by the headlight buckets. One of mine was bad and the problem followed the relay. I've got a few good tested ones in the buy/sell if you need one. I also know for sure a few isolation relays at the local picknpull I can get as well. Good luck
IP: Logged
Bloozberry
Member
Posts: 7760
From:
Registered: Jan 2009


Feedback score: N/A
Leave feedback





Total ratings: 307
Rate this member

Report this Post04-15-2014 08:34 AM Click Here to See the Profile for BloozberrySend a Private Message to BloozberryEdit/Delete MessageReply w/QuoteDirect Link to This Post
It's not the headlight relay because he's already found that there's no voltage on the blu/wht wire coming from the iso relay.
IP: Logged
McCool
Member
Posts: 302
From: Canada
Registered: Sep 2006


Feedback score: (1)
Leave feedback

Rate this member

Report this Post04-15-2014 07:42 PM Click Here to See the Profile for McCoolClick Here to Email McCoolSend a Private Message to McCoolEdit/Delete MessageReply w/QuoteDirect Link to This Post
Thank you for the tip. It's snowing outside right now so I will give that a shot tomorrow when it is nicer.

Are there any side effects from hot wiring it the way you mentioned?

As an alternative, Could I just hot wire a line connecting from the Blue wire (Left Side) to the Blue/White (right side) so the relay is still in place and doing half of whatever it is supposed to do?
IP: Logged
Bloozberry
Member
Posts: 7760
From:
Registered: Jan 2009


Feedback score: N/A
Leave feedback





Total ratings: 307
Rate this member

Report this Post04-15-2014 09:43 PM Click Here to See the Profile for BloozberrySend a Private Message to BloozberryEdit/Delete MessageReply w/QuoteDirect Link to This Post
You should be OK to do as you suggested...but the contacts for the blu/wht wire inside the isolation relay will probably burn out faster because of the extra current being passed through them. Once that happens, you'll have to go to my suggestion where you remove the relay entirely. When you jump the wires either as you suggested or as I did, just be certain to use a jumper wire that's equally large in diameter as the OEM wires you're jumping together to make sure it can handle the current.

[This message has been edited by Bloozberry (edited 04-15-2014).]

IP: Logged
indyguy888
Member
Posts: 255
From: pa
Registered: Feb 2011


Feedback score:    (14)
Leave feedback

Rate this member

Report this Post04-16-2014 03:25 AM Click Here to See the Profile for indyguy888Click Here to Email indyguy888Send a Private Message to indyguy888Edit/Delete MessageReply w/QuoteDirect Link to This Post
Do you have the 87 or 88 fiero ? This would be the second gen headlight set up. Mine was doing the same thing last year. I pulled the module (usually located up under the drivers front quarter panel). I bought another one and hooked it up under the headlight bucket, and walla !!! They both go up and down as they should.

IP: Logged
Bloozberry
Member
Posts: 7760
From:
Registered: Jan 2009


Feedback score: N/A
Leave feedback





Total ratings: 307
Rate this member

Report this Post04-16-2014 08:14 AM Click Here to See the Profile for BloozberrySend a Private Message to BloozberryEdit/Delete MessageReply w/QuoteDirect Link to This Post
He mentioned he's tested the voltage from the isolation relay in his first post, so this is a Gen 1 system.
IP: Logged
McCool
Member
Posts: 302
From: Canada
Registered: Sep 2006


Feedback score: (1)
Leave feedback

Rate this member

Report this Post04-21-2014 08:19 PM Click Here to See the Profile for McCoolClick Here to Email McCoolSend a Private Message to McCoolEdit/Delete MessageReply w/QuoteDirect Link to This Post
Hey Bloozeberry,

What are the side affects/risks of bypassing the relay? What do I need to be worried about?
IP: Logged
McCool
Member
Posts: 302
From: Canada
Registered: Sep 2006


Feedback score: (1)
Leave feedback

Rate this member

Report this Post04-24-2014 12:31 AM Click Here to See the Profile for McCoolClick Here to Email McCoolSend a Private Message to McCoolEdit/Delete MessageReply w/QuoteDirect Link to This Post
bump
IP: Logged
Bloozberry
Member
Posts: 7760
From:
Registered: Jan 2009


Feedback score: N/A
Leave feedback





Total ratings: 307
Rate this member

Report this Post04-24-2014 06:58 AM Click Here to See the Profile for BloozberrySend a Private Message to BloozberryEdit/Delete MessageReply w/QuoteDirect Link to This Post
Personally, I can't see why there would be any side effects.
IP: Logged
PFF
System Bot

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