so I got my Fiero as an unfinished project so trying to find the cause of the no power is a lot harder. I have only got power to it once like a month ago when my friend got the hazards stuck and then randomly the hazards started flashing until the battery died a few seconds later.. btw the car literally has no power at all anywhere. I do have some theories tho.
the first 3 photos are this black box thing by the battery. my dad says it is part of the wiring harness. As you can see it seems to be very corroded. Do I need to replace this or can I clean it.
the next 2 photos are the battery cables. they are quite rusty and have some green so it seems to be corroded copper.
the last 2 photos are in the cab coming from the ECM. I did find the cigarette lighter but have no idea where it connects. I also can't find where the other plugin goes to.
Judging from the pictures your unfinished project has been underwater. The fuse panels are totaled and way too much rust and corrosion on the connectors, cables and metal panels. Just my opinion; Harry
Judging from the pictures your unfinished project has been underwater. The fuse panels are totaled and way too much rust and corrosion on the connectors, cables and metal panels. Just my opinion; Harry
I think what happened was it was sitting for 30 years without its deck lids. all of that snow and water just landed on the electronics. that's why I bought them to hopefully prevent more damage. and they look nice on the car.
so I got my Fiero as an unfinished project so trying to find the cause of the no power is a lot harder. I have only got power to it once like a month ago when my friend got the hazards stuck and then randomly the hazards started flashing until the battery died a few seconds later.. btw the car literally has no power at all anywhere. I do have some theories tho.
the first 3 photos are this black box thing by the battery. my dad says it is part of the wiring harness. As you can see it seems to be very corroded. Do I need to replace this or can I clean it.
the next 2 photos are the battery cables. they are quite rusty and have some green so it seems to be corroded copper.
the last 2 photos are in the cab coming from the ECM. I did find the cigarette lighter but have no idea where it connects. I also can't find where the other plugin goes to.
honestly that corrosion is less bad than my gt that sat in Washington weather untouched for 20 years. clean it up with some contact cleaner and a brass wire brush and get a cheap test light. at this point of going through 120 multimeters from them breaking, getting stolen or getting weird from age the test light just goes so much further. my guess looking at everything is that you need to clean everything and trace power for probably about 10 minutes and youll find the real issue also your other plug is the aldl. unless your talking about something i can't see cigarette lighter screws to the arm rest center console bit btw.
Judging from the pictures your unfinished project has been underwater. The fuse panels are totaled and way too much rust and corrosion on the connectors, cables and metal panels. Just my opinion; Harry
That’s not the fuse panel. It’s the primary power connection block. The gooey stuff in the block is the mastic to waterproof the connections. Your fuse block is located under the dash on the driver side. Squeeze the tabs together to pivot the fuse panel down.
If you don’t have any power at all it sounds like you4 fusible link may have opened. I suggest you get a copy of the shop manual and refer to the wiring diagram and chase the wiring. Get a multi-meter if you don’t have one. You can find serviceable ones at Harbour Freight.
You can search the archives for a link to download a copy f the service manual if you don’t have one.
Carlin said that the original owner ran the engine without oil; pulled the motor out; installed another, and then the "old guy" died before hooking up the unknown second engine...
Carlin also commented that he got the car for free, he is a 16-year-old teen who doesn't know much about engines or vehicles, and I said on Sept 11, 2025:
quote
I'm an 'old school' guy and use printed manuals; my suggestion is to buy the Pontiac Fiero Service Manual of your year... If you're a 'digital guy', use *this* link which has most of the Fiero manuals: https://fieroinfo.com/manuals/
Unfortunately, he is still in the dark and asks the weirdest questions you can think of......
Obviously, I'm not the teacher he needs, VN
------------------ Original Owner of a Silver '88 GT Under 'Production Refurbishment' @ 136k Miles
A free car is a good start but from what I see you need to replace ALL the wiring harnesses, sensors, perhaps the fuse box and replace the ECM. Kept outside for so long open to the elements had to ruin quite a bit. With rust and corrosion on everything you may not be able to save much, If the battery keeps dying that is a sure indicator of a short. I would not mess with it and just replace the entire wiring harnesses including the alternator but first confirm that the engine hasn't seized up. This may not be the answer that you were looking for ,but restoration of an old vehicle does take time effort and money in replacement parts. If your budget is not sufficient to buy all new parts there are lots of good used/surplus parts all over the place.
------------------ " 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 "
A free car is a good start but from what I see you need to replace ALL the wiring harnesses, sensors, perhaps the fuse box and replace the ECM. Kept outside for so long open to the elements had to ruin quite a bit. With rust and corrosion on everything you may not be able to save much, If the battery keeps dying that is a sure indicator of a short. I would not mess with it and just replace the entire wiring harnesses including the alternator but first confirm that the engine hasn't seized up. This may not be the answer that you were looking for ,but restoration of an old vehicle does take time effort and money in replacement parts. If your budget is not sufficient to buy all new parts there are lots of good used/surplus parts all over the place.
any chance I could just cut off the plugin and replace it with a new one. buying a whole new harness would be expensive and very complex to redo.
Check all the connections at the power distribution block, it's the diamond shaped one below the connector you are holding. The connector by the cigarette lighter is for an ALDL/ OBD1 scanner.
Originally posted by Carlin: any chance I could just cut off the plugin and replace it with a new one. buying a whole new harness would be expensive and very complex to redo.
Replacing a Fiero wiring harness is very easy, Just unplug the old harness from all the connectors and plug in the replacement. No cutting or complex work needed. as for being expensive I sold my last two for $100. They might be a bit more today. Suggest that you contact Wayne Renninger. He is very fair and may have them. If you are just thinking that powering it up will solve your problems the negative battery cable goes to a bolt on the engine and to the wiring harness. The positive battery terminal goes to the starter and to the connector with the two studs near the battery. If all battery power connections are not firmly made you will blow out the ECM when trying to start. ------------------ " 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 "
[This message has been edited by Dennis LaGrua (edited 11-07-2025).]
