I have e-mailed Buddy Craig with my problems and as far as I can gather knows about as much as anyone about these '85 Fiero headlight motors. He has promised to get with me as soon as he has the time. In the meantime I thought I would put these questions on the forum to see if I can get some additional feedback. You can't get too many opinions, can you? First question: is an isolation relay interchangeable with a regular headlight relay? If not. where can I get an isolation relay? Second question: Is the blue (with a white stripe) power wire going to the passenger side headlight motor supposed to be live all the time or just live (12 volts) when the headlight switch is on? I have about 12 volts there with the headlight switch on. I got my left side motor working up and down by by-passing the isolation relay thanks to Buddy Craig's help. He sent me a headlight switch brush he had lying around his shop. My brrush had fallen off and would only go down when I by passed the isolation relay. My new problem is that my right side motor seems to have died. Both headlights had worked before neither side would rise up again. The motors didn't spin so I don't think I've got a gear problem. I exchanged headlight relays and have determined that they are both good. What can I do now short of rebuilding the motor?

Just for fun, I'll jump in before BuddyC get back to you.

Can the Iso relay be swapped with the others NO!.

The blue/wht wire is the close power so has power on it while the light switch is off. That is the connector you disconnect to leave the lights up since it removes the down power so the motor will not run to close the lights.

Have you followed Buddy's video for testing the motor itself with jumper wires to verify if the motor is good or not. Doing that will allow you to know if the problem is the motors or the relays before the motors.

[This message has been edited by Dodgerunner (edited 12-30-2007).]

quote First question: is an isolation relay interchangeable with a regular headlight relay? If not. where can I get an isolation relay?

The Isolation relay is different. It is not interchangeable (I don't think the plugs will even fit). I see them at Advanced Auto on the WEB.

quote Second question: Is the blue (with a white stripe) power wire going to the passenger side headlight motor supposed to be live all the time or just live (12 volts) when the headlight switch is on?

I believe the Blue/White wire, the one that goes to the "round" connector on both sides, is the "down" voltage. It comes on when the switch is turned off. When the motor completes its downward travel, and the motor override switch is made, the power is then cut to this lead.

Buddy published an excellant trouble shooting guide not too long ago. I made a hard copy I keep in my repair manual. It takes you through a step-by-step diagnosis of motor check, harness check, relay check. Helped me in every case of headlight motor antics.

Doggonnit, Dodgerunner got in before me! Faster typist I guess?!
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Marc in sunny Titusville, FL

84 SE son's car, loaded
85 Coup w/V6 transplant
85 GT newly on the road
86 SE/GT conversion just bought - big plans!

[This message has been edited by Gwain (edited 12-30-2007).]

84-86 Headlight motor assemblies are notorious and as such they resigned the whole thing for the 87 year model. The 87-88 set up is much better, quieter, and more reliable. the relay unit is a single module instead of a series of individual relays. You might want to consider upgrading to the 87-88 set-up and save yourself some grief. You need the relay, the wiring harness from the firewall forward, and the motors. They come up for sale every so often in the mall or on eBay. Or you can just run down to thr wrecking yard and grab everything.

Alternatively, if you want to keep the set-up you have, I would start with a continutiy test before replacing more parts. dielectric greae may do the trick since after plugging and unplugging relays your plugs may have collected dirt, varnish or are just worn.

I just went out and ran a test and I don't have any power going to the right side either in the on or off position. I don't have the motor hooked on to the right side now. I may have gotten my relays mixed up. What I have is 2 relays with the # 5120 10027587 on 2 of them. One one relay is the number10031018 7023. I think the latter is the relay that either Auto Zone or Advanced Auto sold me as a replacement for the isolation relay. I had bought an isolation relay from each store thinking one of them would be right after the first one didn't work. Since then I I had taken my Fiero to the local garage and they lost one of my supposidly isolation relays. They couldn't fix it and said they couldn't get parts for it. I did run a test to see if the left motor was working by by-passing the isolation relay and it did go up and down. I will check with our local Pontiac dealer Monday to see if they have an isolation relay . At least I can get the right # for it. Anyway I am totally baffled as to what has happened. I don't know why there is no power going to the right side unless the relay I have is not ans isolation relay. Or am I wrong, should there be power in the blue striped wire in the off position even if the isolation relay is disconnected? Any thoughts on this ? I'm beginning to think the car has a curse on it. Don

If you have the right iso relay in and it's good you should have power on the DkBlue and DkBlue/wht wires on each side with the switch off.

I don't know if it is the right iso relay but with the headlight switchtin the off position I have about 12 volts on the drivers side blue wire and no volts on the passenger side blue striped wire. So the only conclusion that I can draw is that the iso relay is the problem. Does anyone, on line sell a true iso relay and not an ordinary headlight relay? I'm thinking most companies think they are one and the same. Don

you should only have power to the blue wire when the head light switch is off,
but since you do not have a correct isolation relay, nothing is going to work right.

The isolation relay part number is 10022620. located on the left fender bulkhead.
it might be called a control module in the price books
and i could NOT get a correct part number from any of the autopart stores web sites.
they all want to sell you the headlight motor relay by mistake

the headlight motor control relays are next to each headlight mounted on the assemblys
gm 10031018 and/or 10027587
Oreillys borgwarner R3230
Delco D1874
Autozone MR86
Parts America niehoff DR5049
Napa ECH AR690

bet you will find that if you do the first test that circumvents the isolation relay, everything will probably work correctly.
start at about 6:15 on the first video.
(yes, i accidentally said 12 amp fuse. it's really a 20 amp fuse, but since i was talking about 12 volts early i got that number stuck in my head)




and PS, gm parts direct sells them for 19.97
www.gmpartsdirect.com

[This message has been edited by buddycraigg (edited 12-30-2007).]

I have 2 relays with the number you stated in your message part # 10027587. so that must be the original GM headlight relays. The part they sold me is #100310187023 as an isolation relay. So I don't know if it really is an isolation relay. Unfortunately I now have something new happening, because even when I circumvent the isolation relay the passenger side is dead. No movement jumping the pink to yellow with the lights on. And no movement with the lights on, jumping the yellow to the blue striped wire. My battery is dead now because it has been setting for a few weeks and I left the door open and have been running checks, so I can't do anymore checks for a while. I took the motor off of the passenger side. I was thinking about opening it up and rebuilding it according to your 1-7 video course. (although 1 of your video clips won't work on my computer at least.. I think I could do it all right.What I did notice was that the blue wire on the drivers side was hot with the lights off and the passenger side showed no voltage, I was using a multimeter for my voltage checks. I don't have anything else to use. Would a car light bulb with some wire soldered on be better? I'll check out that web site for the isolation relay part. I may have 2 problems ????? Don

quote Originally posted by centervilledon: I have 2 relays with the number you stated in your message part # 10027587. so that must be the original GM headlight relays. The part they sold me is #10031018**** as an isolation relay. So I don't know if it really is an isolation relay.

that is not an isolation relay

I'll see if I can find a real isolation relay. I e-mailed the site you gave me and I'll check our local Pontiac dealer after work tonight. Thanks for your help. Don

never mind

[This message has been edited by buddycraigg (edited 12-31-2007).]

You are right. Sorry about that. I don't where my head is today. I forgot to take the number with me when I went to the pontiac dealer, those were the numbers they came up with. Anyway, I called them back with the right number and they can order one #10022620 for $33. I might try shopping on- line to see if I can get one a little cheaper. Dealers are always way high. Thanks Don

Wow - excellent tutorial.

Will try it out tomorrow morning (if it doesn't rain!)

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'85 SE 2M6 automatic
'84 SE 2M4 manual
(and working on buying an Indy...)