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I know theres a few threads from members that have rebuilt their airbag diagnostic modules. I didn't find too many on 1994 or 1995s, so I'm creating this thread on what I did so if someone else down the road needs to do the same, its a bit easier.
Why did i re-cap my diagnostic module? Periodically, the airbag light would fail to light and then beep upon starting. Sometimes it would even start flashing and beeping while driving. This behavior was beginning to increase in frequency to the point where I'd have to turn the car off and on 3 or 4 times to get the beeping to stop. My hypothesis was that the capacitors were starting to die on the board.
In the above thread, the process for removing the diagnostic module is documented in detail. I will call out that getting the 3 screws out while upside down under the dash is a beast. The screw at the very top will just taunt you as you slowly get it loose enough to finger twist it out:
In my case, the fuse was fine, the board looked really clean, so I decided to order and replace all the capacitors. Here are the Nichicon capacitors you need to buy for a 1994/95 airbag diagnostic module:
Its a really great tutorial on how to remove and replace capacitors. The only thing I will add thats NOT in the video is temperature. Having a soldering iron that you can control the temp and also being careful not to apply too much heat as to lift and damage nearby circuits is really important. Components for these cars are starting to get unobtanium...so be careful with the temperature.
Also, a good excuse to level up and buy a top quality weller soldering iron
Thanks for this! I planned to do this in the winter and probably re-cap my instrument cluster. That damn airbag light went from flashing 3x now to a solid light...And yes, the caps looked fine physically (last time I took the module out to inspect) but I think it's time they needed to be replaced.
Quick update on this thread: the 95 module looks different than the 94 module! I ordered the caps and verified the parts just in case. Opened up my module, it needed 6x 1800uF (25V 4W) capacitors instead of the 4 3300uF caps. I will update when I order the other capacitors and repair my module...
Update for 95 Owners: You'll need (6) UPM1E182MHD6 - Radial Leaded 25volts 1800uF AEC-Q200 capacitors instead of the (4) UPW1E332MHD6 - Radial Leaded 25volts 3300uF AEC-Q200.
My module went from solid light back to flashing 3 times (indicating an open circuit). There was leakage on the board that could have caused the open circuit, but I will troubleshoot at the plugs first to find out if it's external from the module or internal.
Update for 95 Owners: You'll need (6) UPM1E182MHD6 - Radial Leaded 25volts 1800uF AEC-Q200 capacitors instead of the (4) UPW1E332MHD6 - Radial Leaded 25volts 3300uF AEC-Q200.
My module went from solid light back to flashing 3 times (indicating an open circuit). There was leakage on the board that could have caused the open circuit, but I will troubleshoot at the plugs first to find out if it's external from the module or internal.
Interesting! Thanks for updating the thread. Its so bizarre that there would be a different board between 94 and 95. Good luck. You could do a continuity check on the circuits that looked damaged and eliminate that as a possibility for the open circuit error code. Could very well be an external wiring problem though.
Interesting! Thanks for updating the thread. Its so bizarre that there would be a different board between 94 and 95. Good luck. You could do a continuity check on the circuits that looked damaged and eliminate that as a possibility for the open circuit error code. Could very well be an external wiring problem though.
Checked plugs as per FSM, external connections are perfect. Looks like the flashing 3x is internal to the board. I just re-did my capacitors again and cleaning up the board as best as I can with alcohol and a toothbrush but it might be beyond saving if the leakage damaged the etching. Someone mentioned to me on Facebook that the fuse resistor might need to be replaced, I've checked resistance on every resistor on the board and they are correct. Will continue to update thread when I replace the resistor since it's an easy replacement.
09-12-21, 03:59 PM
