Hi all new here trying to help a friend who doesn't know the power of forums.

So here is the deal, what we have is a '93 Chevy Silverado 2500 with a fuel injected 5.7L, the other day he was driving down the road and it just died.

We have narrowed it down to some where in the lights (I think) If the the headlights are on and you hit the breaks the truck dies,with the lights off and and just the break lights it will still bogs down and almost dies. we are slowly going through and trying to check every inch of the wiring harness but it is time consuming, so any help that might point us in the right direction would be greatly appreciated.

Edit: also if you need any further info just ask, electrical systems are not either of our strong suit.

 

That's a new one for me.
First thing I'd do is check all the grounds and power connections. Dash grounds, engine-body, engine-frame, battery-body, cable ends etc. Was there any major work done recently like engine swap, heads etc? Then there is the possibility of a failing ignition switch not allowing the ecm to get clean full power.

Hope that helps.

 

I agree with Diesel Dan. If the ECM doesn't see good ground, strainge things happen. Next question I would have ... has there been any steering column work? Brake pedel /stop lamp switch tampered with?

 

I would put a volt meter across the battery with the truck running. Voltage should measure around 14.5V running and around 13V not running (no alternator voltage). Step on the breaks and see what the voltage does. If you have no charging, the battery could be weak and the additional load pushes it over the edge. A battery that weak should be giving other symptoms but at least that's a place to start. Let us know what you find and we'll go from there.
Good luck.

 

well after 2 evenings working on it we have isolated it to the running/break lights by removing the fuses, with both of those out there is no more problem. so we ran some running lights and put the break light fuse back in as the break lights don't kill it just bog it down so he can drive it until we can replace the taillight assembly and run down all those lines until we locate the problem. Thanks for all the input this one had us banging hour heads pretty hard but at least we have it narrowed down a little bit.