Electrical Problems
Thread Starter
3rd Gear
Joined: Feb 2006
Posts: 3
Likes: 0
Electrical Problems
I have an 84 corvette that is exhibiting a number of electrical issues: First the security system is activated when I use the driver side door, but not the passenger, the chime goes off when the lights are on and the motor is running, cooling fan is working intermittently (changed relay), no warning are being displayed, tried to read the computer and received no output. Is it time to replace the ECM?
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Driver doorjamb switch is not being activated either mechanically or has an open ground wire (usually due to corrosion), check it out. Same goes for the chime, security thinks the driver door is open when you are underway, but I would think the security light on the dash would be blinking. Unplug the fan motor and jump 12v to it and see if it also runs intermittently. Fan motors usually fail because the brushes become worn out and no longer reliably connect to the commutator. Parts stores have fan motors cheaper than GM. If motor runs continuously while jumped, then measure the green/white (on my 87) wire on the relay which goes to the ECM and see if its voltage remains low (below 1 v) while the fan should be on, then measure if the red wire has 12v all the time and the black/red wire has 12v when the relay is energized (colors from my 87). Check the ground connection at the motor wiring harness plug, may be corrosion making intermittent ground.
