I've been told that many mysterious electrical maladies can be attributed to bad grounds. I have checked the Haynes manual and found at least 5, maybe 6 grounds shown in the diagram. The problem is, of course, that there is no description of the physical location of each of these. I know about the one at the back of the passenger side cylinder head, and the one in back of the relay "bundle," behind the brake booster, but does anyone have any idea where the rest of them actually are? I, like so many of you on this board, have my erratic idle/intermittent ignition cut out problem back again, and it's time to get serious and clean up the electrical system. Also, do Mass Airflow Sensors generally fail "catastrophically," or do they go out over time?

 

not sure about the MAF but for grounds you can just make your own. My winter beater is a jetta and they are VERY sensitive in the electronics department. just make sure the engine is grounded well to the body and the body groudned well to the battery. then just check over the ground for you computer and see if it encounters any corrosion or anything.

 

Main grounding points are behind the pass. head and behind the driver's side head also. They do work loose and cause problems. Also, real common for other connectors to corrode, even in the weatherpack sealed ones. Just unplug and reconnect all of them, even at the ECM, a couple times to maybe clean them. These problems are sure hard to track down.

 

Thanks guys for all your input. You might want to check this out, too. My battery is on the passenger's side, and if you look on the radiator core support area just in front of where your batteries are mounted, under the "lip" of metal, there is a ground node with four or five wires connected to it. I can only assume that these are the ones represented in the wiring diagrams in the back of the Haynes repair manual. Is this correct?