The 9 volt would probably work but might draw a little more current at the slightly higher voltage. (since we don't know the specs on it). You might try cutting the trace to the relay coil and bridging it with a resistor around 22 ohms and see if it still works which would reduce the current a little. (as long as the relay still operates that way. ) It might be fine even without a resistor.

Really 9v coil? You could do it... Probably the relay will work for sometime... Then rebuild module again when relay fry... Remember car run at 14-15v when alt is on. OE part is 12v coil. (see https://www.fiero.nl/forum/Forum2/HTML/110277.html ) Relay work fine 125% over volt but 150% or more? coils life major cut.... Maybe a resister would help...

No heatsink because maybe GM uses MOSFET is over rated on amps... Part Doesn't need much heatsink and circuit board copper is good enough. Design was good enough to last 20+ years or more...

You original problem likely is module got wet and causes corrosion or board to swell. (Many Board material doesn't like water.) MOSFET's minimal heatsink reduce to nothing when rivet get stretch...

------------------
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 (It's also at the top and bottom of every forum page...)

[This message has been edited by theogre (edited 05-08-2011).]

quote Originally posted by theogre: Really 9v coil? You could do it... Probably the relay will work for sometime... Then rebuild module again when relay fry...

What I don't get is that this module is listed everywhere (including your cave) as the one meant for the Fiero. Part number = 16523917. But looking at the PCB, I don't see how it even can work since it's wired completely different. Not to mention it uses a different relay.

quote You original problem likely is module got wet and causes corrosion or board to swell. (Many Board material doesn't like water.)

Nope, no trace can be seen any water ever got into the module. Car is always parked inside a public parking building.

quote Originally posted by Cliff Pennock: Nope, no trace can be seen any water ever got into the module. Car is always parked inside a public parking building.

are you 1st owner? Force to drive thru large puddle? Maybe the plug(s) weren't sealed and let water in when driving in bad weather. water damage can be way old. Just needs time to work... days, months or even years, to rot out parts.

Corrosion at large terminals area in your post is one artifact shows water got in at somewhere in it's history. Even if GM used Metri-Pack plugs...

The P/N in Cave and others has been ordered many times.
see also nalley gmc, 88 Fiero HL parts item 032
Click "View" next to it and see "Product Fitment/Applications." Corvette uses it til 2004.

You looked at a PCB? Maybe your source of parts gave you wrong module... Mislabel part etc...

quote Originally posted by theogre: You looked at a PCB? Maybe your source of parts gave you wrong module... Mislabel part etc...

PCB doesn't have a part#. ALso, it the module was sealed and it didn't look like it has ever been opened/resealed...

I'ld love to help, after the other attempts have failed.

quote Originally posted by Cliff Pennock: ALso, it the module was sealed and it didn't look like it has ever been opened/resealed...

Seal of module doesn't matter much if Metri-Pack connector fails... Metri-Pack uses 2 seals and either/both can fail. Wire seal can "fail" by pulling wire and keeping silicone seal from sealing. Water can go thru Metri-Pack connectors when wires are pull or bend and wire seal get out of spec. The location of the Fiero's module tends to bend wire too close and pull wires. One or two wires can force Metri-Pack's wire seal to let water in....

MOSFET's "Heatsink"

Source picture, https://www.fiero.nl/forum/Forum2/HTML/112597.html
Using PCB as heatsink is common design. Design is uses when Designer has enough board area and part to cool doesn't need much cooling. Using MOSFET that is over rated will help. Plus Time, MOSFET runs 1-2 seconds max most days...

Fixing module again? Better to chuck it.

Forensics on MOSFET fix and Likely why it fries other MOSFET? Module can't see motor load. MOSFET runs until timer runs out and shut off. Worse, motor is in Stall and spike amps to max circuit allows... IE. 20 amps or more to a short. Even with your added heatsink, will fry the MOSFET, relay, and motor. Be thankful that the module uses a timer to shut off motor and kept you from having a fire.
Can't see motor load? Any small crack in solder on PCB would do it. Delco and some contractors are great for sucky soldering.
Why did new MOSFET fail in spectacular ways? New MOSFET likely upped rated of amps. Added Heatsink made MOSFET last longer.

If fact is problem maybe the reason why OE MOSFET fried and maybe not water damage that I originally thought.

Should anyone fix MOSFET? Most people? No. Most will miss why MOSFET can fail. Failing MOSFET can be a symptom for other problem.
See https://www.fiero.nl/forum/Forum2/HTML/112597.html
A warning will be added to cave.....

------------------
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 (It's also at the top and bottom of every forum page...)

[This message has been edited by theogre (edited 05-09-2011).]

Hi Cliff, sorry. I couldn't find the module. I must have already given it to someone else.

I'll ask around and see if I can find one if you still need it.

Ok, I tested the Corvette module (part #16523917) and it does not work in my Fiero. I opened it up and it didn't seem it has ever been opened before (it was sealed). Looking at the PCB and following the traces coming from the relay, I don't see how this can work in a Fiero. So either the PCB has been replaced in this module (although again, it doesn't seem it has ever been opened), the module is broken (I bought it new) or every other site on the internets is wrong about this particular part number being compatible with the Fiero.

Either way, I still don't have a working module so I'll gladly take up on one of the offers...

If you read that post I did the link to you can see how some of the firebird modules do work. They could be made to work in a Fiero with a little wiring mod. I'd check it functions with the input I listed first if you do want to try it.
Some of them use a +12 for up and ground signal for down instead of just +12 inputs for up and down.


https://www.fiero.nl/forum/Forum2/HTML/113825.html About 7/8 of the way down.

[This message has been edited by Dodgerunner (edited 05-11-2011).]

quote Originally posted by Cliff Pennock: Comparing the PCB of the new module with pictures I found on the Internet, I found out it isn't a Corvette module but a Firebird module. I bought this module 2 years ago on eBay. Guess I got ripped off.

Depend on model year... Firebird uses both... 87-89 gets 16523917, 90-02 gets 16525685
Example nalley firebird module

------------------
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 (It's also at the top and bottom of every forum page...)

[This message has been edited by theogre (edited 05-11-2011).]