Lynns

My 1999 Suburban is having an electrical problem. All the lights and gages flicker off and on occasionally. Sometimes the engine and all power goes out for a few seconds then everything is fine. I found an engine to body ground strap that is touching the exhaust manifold. The strap is frayed and starting to deterioate a little. Can this be the problem? Any help or suggestions would be appreciated. Thank you.

grumman

a good ground is critical. in my opinion, replace it.

Chuzz

I agree with grumman about replacing that ground strap, but I'd have my local Autozone or Advance check the alternator. You may have a brush sticking in it and causing the flickering. How many miles are on it? They can test it on the vehicle with their portable ARBST tester. Don't let them tell you any different.

therewolf

This ground strap, presumeably, is still connected at both ends? I would highly recommend replacing the ground strap, and the pos and neg battery cables. This will level the playing field, and further troubleshooting, if needed, can start from a solid foundation.

89Grumman350

Either way your frayed ground cable/strap should be replaced. However, this is not your problem. A ground cable grounding out on your exhaust manifold will not make any difference with your symptom, but should corrected either way.
It sounds to me your electrical system has been tampered with, and you should check that all of your connections are tight and secure. Having your alternator checked for proper output is also a good suggestion. It should be atleast 13.4 volts and typically no more than 14.3 . Note back with your results.

thomatt12

I agree with what Gruman said. A good grounding on your ride is indeed critical. Just have it replaced. It's for your own safety too.

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Kin Bineola

I just solved this one myself. Yes, it is an engine ground problem. This is a 30-minute task because of difficult access. The faulty ground is at the back of the engine. From the PASSENGER side, open the hood, and look at the rear of engine. Find the black wire loom that is about 1.5 inches in diameter. Coming out of that loom is one single wire that covered in a black flexible wire loom protector, and it is the diameter of a soda straw, that comes out of the loom, and it goes down toward the back of the engine, where it attaches to a bolt in an O-ring wire clamp. Get a beer, and spend 5 minutes searching until you find this wire in its loom.


Now, from the passenger side, get up on the fender, lay across the coolant reservoir and other engine bay parts, and feel (you cannot see, you must feel with your fingers) to confirm that the wire loom goes down on the back of the engine until it ends on an O-ring wire clamp, attached to the engine via a 13-mm hex bolt, and the bolt is pointing down toward the ground. That is, a small ledge comes out of the back of the engine and the ground bolt is screwed into this ledge. Now that you've bruised your chest and belly tracing this wire, here's how you fix it.


Go buy a flexible universal joint adapter, and get back up onto the engine, tie kite string to your tools, so you can retrieve them when and if you drop the, and get that connection disconnected at the engine. [You ned that flexible universal joint because there are obstructions that prevent you from doing a simple ratchet-on-the-socket motion.]
Put a 13-mm socket on that grounding bolt, and then put about a 6-inch extension bar, then your universal joint adapter, then a 12-inch extension bar, then your ratchet. Carefully loosen the bolt, remove the bolt, and now you can examine the damaged O-ring connection. Now you will see what's the problem. The wire is just about completely broken off of that metal O-ring connector. Due to fatigue, the 10 strands of wire have fractured, and only 1 or 2 wires are not broken and connected. The other 8 wires which are broken, "touch" for an intermittent connection, but when you go over a bump, they come apart, you have an insufficient ground, and all hell breaks loose on your instrument cluster. The repair is simple in concept, but difficult to reach. The solution is to repair that ground.


Solution 1: Ground that damaged wire elsewhere. Do a splice at the O-ring (discarding the O-ring) and run 2 feet of new wire over to the ground on the Driver side of the firewall (or any other place you know you have a reliable ground). I used a nice O-0ring connector at the driver side firewall and just added it to the woven ground strap that is already there.


Solution 2: Cut off the damaged O-ring metal connector, buy a new O-ring that has a big enough diameter that it will fit that 13-mm bolt, splice the existing wire to that new O-ring, and reinstall the new O-ring metal connector (that now is connected to undamaged, unfractured ground wire) back to its original spot on the back of the engine.


I did both solutions, and it solved ALL of my instrument cluster problems.
Good luck. And aside from this issue, aren't these trucks amazingly reliable?

itsjrs041

Kin, You are my God. Thank you for such a detailed answer to such a pain in the @$$ problem. One would think, at GM, that since this is an on-going problem, effort in some form or another, could be passed on to the general public.