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on my 79 its behind the dash to the right of the glove box.the glove box has to come out to get to it.it should be an orange colored relay looking thing.i have the same problem and have yet to find a replacement.
i think its a yellow box, infront of the glove compartment. Before you accuse that guy, check your grounds and switches. The way the system works is that when you open your door, it allows the switch to make and provides a ground, this goes to the delay module which will hold the ground even after the door closes for 2 minutes or whatever it is. If you have a bad ground switch, it will always be calling and seem like the timer delay is the problem. good luck
I read all the replace & bypass suggestions but I went one step farther. B4 replacing module for $40 just replace the transistor on the board.. it is attached to the heat sinc with a clip and the 3 pins are soldiered to the board I pirchased the part for $.96 plus shipping
I read all the replace & bypass suggestions but I went one step farther. B4 replacing module for $40 just replace the transistor on the board.. it is attached to the heat sinc with a clip and the 3 pins are soldiered to the board I purchased the part for $.96 plus shipping
I read all the replace & bypass suggestions but I went one step farther. B4 replacing module for $40 just replace the transistor on the board.. it is attached to the heat sinc with a clip and the 3 pins are soldiered to the board I purchased the part for $.96 plus shipping
Do you have any pics and transistor info? My board is bad, I bypassed it and the lights work, so at least that part is good. My board shows corrosion by the terminals, would like to save it if possible. I've got a plan to use a separate relay/timer device, but saving the board would be. A bonus.
Do you have any pics and transistor info? My board is bad, I bypassed it and the lights work, so at least that part is good. My board shows corrosion by the terminals, would like to save it if possible. I've got a plan to use a separate relay/timer device, but saving the board would be. A bonus.
Thanks!
The transistor is a MJE3055TG availible from Mouser Electronics (www.mouser.com) cost was $.96 (96 cents) plus shipping etc here is pix with heat sync removed (metal plate)
The transistor is a MJE3055TG availible from Mouser Electronics (www.mouser.com) cost was $.96 (96 cents) plus shipping etc here is pix with heat sync removed (metal plate)
No problem.. and it's a great repair thread.. I make the timer boards and I don't care if you found a way to repair it.. That's great news and a cheap fix... but you might want to post your repair in the C4 section so that those with c4's will know how to check things. Some people would rather buy the board and move on..
Now for you.. C4 cars have a inherit issue... The rear hatch (on coupes) and the rear deck lid (on convertibles) have a release solenoid.... The solenoid takes a huge hit when activated and if your rectifier in this circuit is bad the voltage spike will hit the board and blow it... Replacing a resistor and or replacing the board if there is a rectifier issue is just a band-aide... The spike will take out the new resistor and/or if you purchased a new board from me it would take out the new board because the mosfet can't take the spike... and when this happens you end up on voltage run-on.... So.. after 12 months of re-thinking the board we decided to make a change that would help the c4 owners...
Last month we made a change in our boards for the c4 cars to the extent that.. Starting in a few days, we are going to re-design the circuit boards to accept a new Mosfet that will suppress the voltage spike. The new Mosfet, IRF540n is capable of taking 1000 volt spike and this should suppress any spike coming in from the rear hatch release. This is a way better design and one that GM didn’t think about when they made the board originally. Basically we’re going to amp up the board so that it will act as a rectifier for the hatch release.
No problem.. and it's a great repair thread.. I make the timer boards and I don't care if you found a way to repair it.. That's great news and a cheap fix... but you might want to post your repair in the C4 section so that those with c4's will know how to check things. Some people would rather buy the board and move on..
Now for you.. C4 cars have a inherit issue... The rear hatch (on coupes) and the rear deck lid (on convertibles) have a release solenoid.... The solenoid takes a huge hit when activated and if your rectifier in this circuit is bad the voltage spike will hit the board and blow it... Replacing a resistor and or replacing the board if there is a rectifier issue is just a band-aide... The spike will take out the new resistor and/or if you purchased a new board from me it would take out the new board because the mosfet can't take the spike... and when this happens you end up on voltage run-on.... So.. after 12 months of re-thinking the board we decided to make a change that would help the c4 owners...
Last month we made a change in our boards for the c4 cars to the extent that.. Starting in a few days, we are going to re-design the circuit boards to accept a new Mosfet that will suppress the voltage spike. The new Mosfet, IRF540n is capable of taking 1000 volt spike and this should suppress any spike coming in from the rear hatch release. This is a way better design and one that GM didn’t think about when they made the board originally. Basically we’re going to amp up the board so that it will act as a rectifier for the hatch release.
Willcox
Thanks for your input and hope your rework is successful I like keeping things totally original in all aspects though besides it took 32 years for the original to fail. As far a s my posting in C3 it was a reply to the one wiith a pix of the board.
Thanks for your input and hope your rework is successful I like keeping things totally original in all aspects though besides it took 32 years for the original to fail. As far a s my posting in C3 it was a reply to the one wiith a pix of the board.
No worries.. It's all good info for any thread.
My re-work will work, I've already tested it. The biggest issue we have with the timer boards (and almost all the boards we make) is that customers think the board is the point of failure... In most cases if the board fails it was zapped. Our first run of the boards didn't have a fuse, the second run and last run did.. This told us if the board was zapped somewhere else or if there was a failure on the board. But what we kept seeing was a backwards spike on the boards (on the 84 and newer cars) and this is what lead us to investigate what was causing it. The new Mosfet will be able to absorb the spike and should solve that issue... But as with anything electrical... replacement boards that are tested can't fix an issue somewhere else.