Electrical Problem...
Thread Starter
Instructor
Joined: Jan 2007
Posts: 163
Likes: 1
From: Reedley, USA California
Electrical Problem...
I have a 1993 coupe. What does the 3 amp diode do in the power seat circuit? (It's on the power seat switch connector in the center console.) Can I do without it? Mine is shorted and I'm having some trouble finding one in my area to replace it.
Safety Car
Joined: Feb 1999
Posts: 3,504
Likes: 4
From: Mexico Beach FL
The diode absorbs unwanted voltage transients caused when the motor (an inductor) runs and is shut off.
The long answer:
When any inductor (including a motor) is energized, a magnetic field builds up around the coil (the motor winding).
When the power is shut off to the inductor (in this case, the motor), the magnetic field will collapse inducing a voltage into the inductor.
The purpose of the diode is to absorb that voltage (electrical noise) and prevent it from getting back into the main power supply (in this case, the battery).
It probably prevents you from hearing a "click" in the radio when the power seat is energized and turned off.
Normally, you will find a diode across the A/C compressor clutch windings for the same reason.
Tom Piper
Last edited by Tom Piper; Jan 20, 2008 at 12:22 PM.
Racer
Joined: Sep 2007
Posts: 393
Likes: 0
From: Bartonville Illinois
Diodes
If you have the Factory service manuals, under intermittent problems you will see that there are a number of diodes in the car. Transients caused by the absence of a diode in a circuit can cause other problems. If you know the diode is bad, I would replace it. You can also get them at places like Newark Electronics.
You have already done the hardest part of the job by taking the console apart.
You have already done the hardest part of the job by taking the console apart.
Thread Starter
Instructor
Joined: Jan 2007
Posts: 163
Likes: 1
From: Reedley, USA California
Managed to find a Radioshack 50 miles away that has the 3 amp diode (gotta love living in a small town...). Should have my car together again tomorrow...
My dad was wondering if there was just some way of bypassing the diode. Thanks for the input, guys!
And yes, I know it's shorted out... I hop in my car to head to the college and my car seemed deader than a door nail. Put the jump cables on it and had some sparking and pulled fuses until it was driveable again and tracked it down to the fuse for the power seats and then had to 'hotwire' the seats for further diagnostics.
My dad was wondering if there was just some way of bypassing the diode. Thanks for the input, guys!
And yes, I know it's shorted out... I hop in my car to head to the college and my car seemed deader than a door nail. Put the jump cables on it and had some sparking and pulled fuses until it was driveable again and tracked it down to the fuse for the power seats and then had to 'hotwire' the seats for further diagnostics.
