by Pat Goss
On today’s cars and trucks, a little piece of wire like this and a screw can cause monumental electrical and electronics problems. You see, modern cars have all sorts of computers so that means they have to have absolutely clean good electrical connections.
Now everybody’s familiar with checking the positive side of things to make sure that the power is getting there but I can tell you when in a repair shop we find almost as many problems in the ground or negative side of the circuits as we do the positive. And a lot of the problems that are associated with poor grounds, well they can be very confusing.
The other day we had one in where we turned the headlights on and one headlight was dim, the turn signal below the headlight very slowly and very dimly flashed, and there were warning lights that lit up and flashed very slowly on the instrument cluster. Well, we got to checking this, and of course the power supply was good to all of these things and we found that it had a poor ground.
Now in many cases the ground for the headlight and so on is going to be up here in the front right beside the radiator and it’s exposed to all kinds of slop and everything from the road so these are prone to corrosion. Same with a lot of them under the hood of the vehicle. So if you have a really strange problem, start checking the grounds.
Now if you find a bad ground do what we’ve done on this truck. We took the ground wire off and we ground the paint off so that we have a good electrical connection there. We cleaned the bolt and we cleaned the wire. Now, we’ll paint that with liquid electrical tape which will keep moisture away from it, seal it up, and it’ll help prevent future problems. Like with what we see over here. This is on the computer on this truck and we can see that it’s coated with corrosion. So before we’re done, we’re gonna fix that one too.
So strange electrical problems, always check for poor grounds on a modern vehicle. And if you have a question or comment drop me a line, right here at MotorWeek.