95 sonoma wiring prob

I have a 95 Sonoma 4.3Z that has wiring trouble. ABS & Brake lights will flash, power windows and locks fail at this same time as so does A/C and blower motor. I have determined that there is low voltage to these items when this happens. I am thinking bad ground. My question is where are the grounds and if they are all at the back of the cylinder heads, how do you reach them. I have tore a portion of my dash out looking for interior grounds but have found none.

when does this problem happen, is it when you are driving or at idle, or is it with the engine off?

it sounds like your problem might be a bad ground from the battery. did you check your connections on your battery terminals for corrosion? if it happens when the truck is off, that might be your problem. also check connections on your alternator, since that is what powers your accessories when the engine is running.

as for the grounds, i think the devices like locks and windows ground on the door or the chassis nearest the device. the ground for the ABS and brakes is in a different location and not the same wire, so thats why its probably the connection on your battery or alternator, or a bad connection with the negative battery cable and the chassis. trace the negative battery cable and you should find a couple places where it connects to the chassis and engine, those grounds are probably corroded.

Hi Spitfire. The problem was occurring occasionally at idle-while driving down the road-when turning on a/c-rolling down windows. Now how ever the problem is constant. I pulled fuses from fuse panel and with good old trusty test light I found 4 circuits with low voltage. That pretty well eleminates a ground problem and leaves me with a connection problem on one or more of my 12 volt sources for these circuits. Thanks