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Old 08-03-2006, 04:44 PM
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dimming lights

Hi again!
What would cause my lights (radio,head,dome..) to dim when I press the brake --and they go back to normal when I release the brake???
I never had this problem before.

I just recently cleaned up all my ground straps (about 3 months ago) and they are all fine. I even added 2 more ground straps. Everything I could think of got a strap.

Should the alt. (100amp)have a dedicated ground or is the block good enough?

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Old 08-03-2006, 04:46 PM
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could be a bad ground or a bad alternator that cannot make up for the extra sudden draw.
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Old 08-03-2006, 05:27 PM
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Doc here,

First, AS always..we assume you have already pulled and cleaned the battery cables..AND inspected the belt for loose conditions..

The Alternator SHOULD have a dedicated ground..There is a lug at the back of the alternator for just that purpose..Hardly anybody uses it..and end up with this problem over time..

What happens is the Alternator will corrode, and turn power white..along with the mounts..(they are electricity run in copper, aluminum on Steel in the presents of water stream..what the heck were they thinking?) This is electrolysis..will insulate the alternator..EAT it and a water pump faster than an acid..Should this be the malady in your case.

Run a 10 Gauge ground wire and Graft it into your Ground Buss system. IF you don't have a proper ground buss system (and most don't...) construct one..it's easy to do..just do this:

Run a properly gauged Ground cable from the battery to any handy bolt at or near the starter, From that same bolt get a Battery cable at the parts store, that has two 3/8 ring terminals on each end and attach it there and to the Frame.

Next get some 10 gauge wire and ring terminals and run that from your bolt on the block to the Firewall, and another to the Alternator bracket or mount bolt.

If the Bracket and alternator is power white remove them both and their hardware, sand or pressure wash them until clean semi shiny metal, dry and reinstall.

You have electrolysis there..and it will also eat a water pump impeller up faster than any acid..The Alternator Bracket and Alternator housing is Aluminum and the block is Steel..

When you go to reinstall the brackets, go to the hardware store and get some aluminum wire compound, and coat everywhere the mount hardware meets steel (bolts, mount surfaces Ect..)

Next get some Wire Braid, (Radio Shack) and install braid from the radiator support to the frame, Fenderwells to frame , hood to firewall, Doors to door posts, gas flap to body, tailgate / Trunk to body.

At each point the wire is grounded, Burnish ALL the paint and grease off to bare metal. Use a proper star-washer and lock. Use sheetmetal or Tech screws where no screws are available.

It sounds like a lot of work, but after you assemble all the parts, it's only a few hours to do..and you'll end up with a system that will work reliably for many years to come..and can eliminate that from your troubleshooting list.

IF you still have the problem, Take a voltage reading at idle..DVOM set for DCV , V X 50.. it should read 13.95 to 14.4 Volts. If not raise the idle a bit see if it comes up to 14.4..if so, and is EXTERNALLY regulated..adjust the air-gap in the regulator..If not..go to auto zombie and have your alternator, and BATTERY tested..repair or replace as required.

Doc
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Old 08-08-2006, 02:52 AM
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I'm going to do that, Doc.
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