94 Chevy 2500 electrical issues

[silveradoTornado]

How bad can a faulty ground mess things up in a truck? Long story short everything worked fine, I pulled the tranny had it rebuilt put everything back together and now I have issues. I don't even know where to start, first thing I noticed is the brake lights quit working, blinkers worked running lights work just no brake lights. Now the strange part the brake light was illuminated on the dash and the engine was surging like something was drawing down on it. soon as I hit the brakes it would quit. I ended up pulling the wires out of the ABS module the dash light went out and the engine quit surging. Brake lights were working so I thought all was well. It started raining so I turned the wipers on much to my surprise they don't work. All fuses are good and can hear them trying to work but they won't kick on. Also when I try turning them on you can tell it's taxing the electrical system as the engine will bog down and sometimes even die. Now even with that black abs deal unplugged the brake lights aren't working so I am guessing it was just a fluke.

I did notice on the passenger side firewall the ground strap form the firewall to the block was broken, looks like there are two straps from the firewall one to the frame one to the engine. I plan to replace that but not sure if that is enough to cause those kind of issues?

 

[ak diesel driver]

There are alot of grounds, you need to clean and repair them all. There's 3 on the passenger side back intake bolt area that are super critical. Personally to me it sounds like you pinched some wires somewhere.

 

[silveradoTornado]

I plan to go back over everything this afternoon, initially looking I couldn't see any pinched wires or anything like that but I obviously done something while I had the transmission out. I really don't want to pay to have it fixed I just bought it for a farm truck and I've already spent alot on the transmission.

 

[Husker6.5]

Yes, grounds are CRITICAL on these! In fact, many of us ADD grounds and with heavier gauge gauge wire/braid to new grounding points between engine/transmission/body/frame and the battery Negative terminal.

A bad/broken ground can often times cause the kinds of problems you describe as current, seeking the path of least resistance, takes any ground possible - including back feeding through other components on the same power circuit that aren't energized and grounding through them.

 

[Will L.]

ever try a flashlight with a new battery but not screw back on the end? grounds are just as important as the power wire. one can not work with out the other.

Examine for pinched or forgotten wires to be connected from the repair- a common oops. beyond that, remove, clan and reinstall all grounds.

 

[silveradoTornado]

Thanks for the replies..... we figured it out. Ended up being the ground wire on the back side of the head on the passenger side. I did take off and clean all of the grounds I could find and also added back that one body ground strap.

Here’s where it started making sense for me. ABS module, windshield wipers, O2 sensor and brake lights were all on this same circuit. I guess when I installed the transmission fill tube I busted that wire. Anyway so with that ground not connected none of the things in that series were getting proper voltages. The O2 sensor explains the surging and poor running condition.

Thanks again