Posted 2005-09-08 3:19 AM (#30049) Subject: Vehicle electrical problem
Elite Veteran
Posts: 610 Location: Northern CA
Hi there all,Anyone out there that is electrically inclined?I have a '91 chevy 3/4 ton that shorts out when I use the brakes, blinker,high-beams,etc. The truck literally shorts out for a millisecond as I am driving down the road!This does not happen all the time though. I took it in to an electrical auto shop ,but of course they could not find anything wrong when they checked it out.I bought this truck used 5 yrs ago and don't remember it having this problem before I had the trailer brake controller and etc. installed. But again , it doesn't happen all the time.I did notice recently that it is now making my trailer lights flicker, alot.Any advice?Thanks
Posted 2005-09-08 7:22 AM (#30053 - in reply to #30049) Subject: RE: Vehicle electrical problem
Expert
Posts: 2689
The high beams clue suggests to me that it has NOTHING to do with the brake controller installation. The brakes AND turn signals suggests that it probably isn't the turn signal high/low beam switch stalk either.
Notwithstanding those comments, iIf you think it came on after the brake controller was installed you could just unplug that for a few days while NOT trailering.
SOooo, I'm guessing that you just a have a plain old short to ground SOMEWHERE - or a bad alternator. How severe IS this short ?
Posted 2005-09-08 8:32 AM (#30061 - in reply to #30049) Subject: RE: Vehicle electrical problem
Extreme Veteran
Posts: 366 Location: Albany, Oregon
A friend of mine had a ground problem in a GM that did some weird things. All that plastic and many grounds. His would back feed and make it do weird things. You might look in that area.
Posted 2005-09-08 8:41 AM (#30063 - in reply to #30053) Subject: RE: Vehicle electrical problem
Elite Veteran
Posts: 610 Location: Northern CA
When my truck shorts out while driving down the road,everything shuts out (engine)just completely dies for a millisecond then there is a jerk when it comes back. scary!
Posted 2005-09-08 8:51 AM (#30064 - in reply to #30049) Subject: RE: Vehicle electrical problem
Regular
Posts: 93 Location: Northwest Indiana
Something similar happened to with my car. Terminals on the battery were so corroded that I would get intermittent connection. Just took cleaning the terminals and replacing the bolts.
Posted 2005-09-08 9:25 AM (#30066 - in reply to #30061) Subject: RE: Vehicle electrical problem
Expert
Posts: 2689
Originally written by xyzer on 2005-09-08 8:32 AM
A friend of mine had a ground problem in a GM that did some weird things. All that plastic and many grounds. His would back feed and make it do weird things. You might look in that area.
There is indeed a COMPLEX grounding scheme in most modern vehicles, not the simple chassis and sheet metal grounds of the 70s.
Not ALL is attributable to the use of plastics, the many computers and their sensors NEED good HF grounds, ground loops can confuse the heck out of them.
Anyway, the O/P on this thread seems to have a SERIOUS short, not a high impedance ground, quite possibly in the alternator.
Posted 2005-09-08 9:46 AM (#30068 - in reply to #30049) Subject: RE: Vehicle electrical problem
Extreme Veteran
Posts: 366 Location: Albany, Oregon
True! A short will usually blow a fuse or circut breaker we hope, or dim lights! A bad ground doesn't. The post didn't mention any fuse or circut breaker problems.
Posted 2005-09-08 11:18 AM (#30076 - in reply to #30049) Subject: RE: Vehicle electrical problem
New User
Posts: 2
On the top of the E brake bracket is a studed bolt (ground for interior lights radio , light switch and so forth ) have seen this work loose and cause some strang things to happen, usually on gm trucks hope it helps. Do you have a DVOM or any type of volt meter that you can do some voltage drops and check for proper voltage?
Posted 2005-09-08 5:04 PM (#30095 - in reply to #30068) Subject: RE: Vehicle electrical problem
Elite Veteran
Posts: 610 Location: Northern CA
No corrosion on terminals, no blown fuses or circuits. I had a friend use the voltometer thing and It didn't show anything either. I also had the Alternator replaced.I t has a new starter and coil as well. But still the problem.This truck is so clean under the hood! I just went out and looked for the studded groud next to the p-brake, not really sure what I am looking at though.
Posted 2005-09-12 7:38 AM (#30209 - in reply to #30049) Subject: RE: Vehicle electrical problem
New User
Posts: 2
The regulator is internal in the alternator-on the ground you may have to remove the kick panel to uncover.What you are looking for is 4 or 5 wires being held onto the side of the body in that area with either a bolt or a nut on a studded bolt.This may help w/lights flickering radio etc. But will have no effect on engine performance.
Posted 2005-09-12 3:41 PM (#30233 - in reply to #30049) Subject: RE: Vehicle electrical problem
Member
Posts: 27 Location: Saltillo, Tn
I had a similar situation with my wife's car. I tooked it to a mechanic to have it checked out. He said that he could not find any bad grounds and suggested that I have the battery checked to see if any of the cells were bad. I did and replaced the battery. She has not had the problem since. So get your battery tested to see if it has a dead cell.
Vehicle electrical problem
