Hi all. I recently became the proud owner of a 1985 GT. Having an issue with the headlight system. Neither motor goes up or down when I used the switch(which was replaced new). I tested each motor and the drivers side motor I can get to move up and down but the passenger side will not. I’m guessing it will need a rebuild. I also have 12v of current feeding through the wiring, so that’s good. Replaced both relays for each motor and they still will not work with the switch. Only thing I’m am thinking is it could be the isolation relay. Any input, would be greatly appreciated.
Hi all. I recently became the proud owner of a 1985 GT. Having an issue with the headlight system. Neither motor goes up or down when I used the switch(which was replaced new). I tested each motor and the drivers side motor I can get to move up and down but the passenger side will not. I’m guessing it will need a rebuild. I also have 12v of current feeding through the wiring, so that’s good. Replaced both relays for each motor and they still will not work with the switch. Only thing I’m am thinking is it could be the isolation relay. Any input, would be greatly appreciated.
One of the best things you can do is rebuild them with Rodney's kit.
Going from a plastic gear (prone to break or worn) to a metal one is a great upgrade.
If the motors run but don't operate the headlight assembly, it's the gears. Witchita gives good advice on replacements. If both don't run, it may be the isolation relay located on the left fender wall, beside the headlight assembly. They are no longer available as new relays. I have a few should you need one.
The motor relays that are mounted on the side of the headlight assembly have the same harnesses, but the circuitry is different. The last 4 numbers of the isolation relay are 2620.
I’m going to run a couple more tests to try and pin point if it’s actually the isolation relay or not. If it is, I would certainly be interested in one of yours.
IMO the absolute BEST thing you can do is to convert from the Gen 1 headlight control system on '84, '85, & '86 Fieros to the Gen 2 headlight control systems found on the '87 & '88 Fieros. You can still buy replacement motors for these systems and the solid state control unit. (It's the same one from a C4 corvette.) You'll need to find a harness, module & motors from an '87 or '88 and spend a couple of hours (about a 2-beer job) swapping it over. Both of my '86 Fieros have the Gen 2 system. Best investment I've made on the lighting system. (I still have the Gen 1 systems and motors. Someday, I'll chase down the differences and convert them to Gen 2 systems and motors.
If the motors run but don't operate the headlight assembly, it's the gears. Witchita gives good advice on replacements. If both don't run, it may be the isolation relay located on the left fender wall, beside the headlight assembly. They are no longer available as new relays. I have a few should you need one.
The motor relays that are mounted on the side of the headlight assembly have the same harnesses, but the circuitry is different. The last 4 numbers of the isolation relay are 2620.
I would be interested in buying one of your isolation relays from you. Would you ship as I’m up on the east coast of Canada.
Sorry. I’m new to this forum. I can’t seem to find any PM messages. I’ve sourced a relay from someone else in another province though. Hopefully that works out.
Also wondering if the limit switches can be replaced? I have removed the passenger side headlight motor and bench tested and there is no power getting to the motor to make it run. There is a small glass tube inside that looks blackish in color and burnt.
I've done the rebuilds are they are not difficult IF you have the right rebuild parts and follow the instructions to a T. The first step is to remove the brush plate and check the brushes. They might be good but if not Rodney sells replacements that can be mounted in place with conductive epoxy. If the springs are worn away or broken then there is little that can be done and the motors are trash. If you glue new brushes in place on the springs wait 24 hours for the epoxy to set before completing the rebuild. The rest of the rebuild involves drilling out the screws opening the case and replacing the rubber bumpers inside the drive gear. If the drive gear looks good it can be used again but if there are any stripped teeth a new gear is required. The detailed process can be found on You Tube in the Buddy Craig Videos
------------------ " 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 "
Traderman- at the first "page" of the forum (Table of contents) look all the way at the bottom where it should say "Inbox" for your private messages (PMs).
I converted my 85 over to the 87-88 system- need a front lighting harness, motor control module and then you can buy new motors (Still available).
The limiter switches are replaceable, but like the isolation relay, aren't available except from another motor. Due to age, you must be careful when removing and installing them to prevent breaking the brushes off. I also have those, but for the thermal bulb and other parts of the limiter switch to be black is normal.
If you have no power going to the motor, swap the relays that are located on the headlight housing to the opposite sides. If the passenger side starts to work, it is the motor relay. Those are still available at most US auto stores so I assume they will also be in Canada.
I've been buying these rebuilt motors from Stanley Miller who has an ebay business. 2 prices, one with nylon gears, one with aluminum. Refund on the cores.
Highly recommended. Yeah, you can rebuild them yourself, but this guy has been doing this for years. It would take you twice as long to do it wrong. Read the description- he's really thorough.
If the link doesn't work go to ebay and enter: 1984-1986 Pontiac Fiero OEM Headlight Motor Actuator Rebuild Repair Service
Hope that helps. -JT
BTW- I've been trying to buy a Gen 2 harness n relay set-up for YEARS (I've had 5 Fieros. Just Saw one on ebay for $500. Bet it's being sold by one of you rascals !
[This message has been edited by JT6666 (edited 11-03-2022).]
I've been buying these rebuilt motors from Stanley Miller who has an ebay business. 2 prices, one with nylon gears, one with aluminum. Refund on the cores.
Highly recommended. Yeah, you can rebuild them yourself, but this guy has been doing this for years. It would take you twice as long to do it wrong. Read the description- he's really thorough.
If the link doesn't work go to ebay and enter: 1984-1986 Pontiac Fiero OEM Headlight Motor Actuator Rebuild Repair Service
Hope that helps. -JT
BTW- I've been trying to buy a Gen 2 harness n relay set-up for YEARS (I've had 5 Fieros. Just Saw one on ebay for $500. Bet it's being sold by one of you rascals !
You can replace the Fiero isolation relay with a standard $8 12V DPDT relay. The instructions for hookup are somewhere here in the archives. In short the isolation relay sends power to each headlight motor relay in a separate path. You could get away with a SPDT relay but that hookup combines the supply path in a single feed. It will probably work but I've never tried it.
------------------ " 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 "
