Weird electrical issue...

[bac078]

I have a 99 GMC 1500 Sierra Z71, and recently it has been giving me some wierd troubles. I will start it up...everything is fine, as soon as I start driving, I lose ALL electrical power for a split second, my radio cuts out, clock stays the same time as current, lights and dials go out and down, then it all comes back on. It comes right back on quickly, and does this about every 5 to 8 seconds. So I stop, turn the truck off, and then I tried to start it and I have no power, lights off, won't start, its as if I have no battery and clock resets to 1:00 once I get it started. After about 10 or so tries, she starts up and I am off and driving...glitches gone and everything. It does this about once a day. Any suggestions or help.

[bac078]

Also When this flicker happens, I do not lose any engine power, I can accelerate and have no hiccups but the flicker will still happen, When I go to a stop light, the flicker stops until I start driving again.

[Giant]

This is strange. I had a similar problem with a cadillac that I owned. The flicker would shut just about everytying down. Lights, dash, radio. but my engine would also just about die. I found my problem to be a less then perfect ground cable on the battery, as well as my battery going bad. Maybe the design of the 4.6l northstar in the caddy made the engine die when parts lost power where the 5.7 doesn't, I don't know.

 

Also you mentioned that it does this while driving. that also leads me to believe its a ground/battery problem as well. THis would be when the engine and surrounding systems would be drawing more power. I noticed the hicups in my caddy most often when I would accelerate. A new battery fixed my problems. Take your battery into a local part store and have then test it.

 

Hope it helps

-robert-

[jjacks01]

I second Roberts advice -

 

Same symptoms in my truck a few years back. Turned out the battery had an intermittent internal short. Replacement fixed it instantly....

 

Good Luck and I hope this is the fix!

 

JJ

[unsolved]

Yep... Had the same problem. Negative battery connection. Check ground straps and ground cable from - battery terminal to body/Frame. Also check big ass connector under dash for melted burnt terminal. The red and yellow wires specifically. The thick ones. Also might want to check fuseable link for s**ts and grins. Good luck.