Firewall Ground

aztecgwynn

Active Member
Apr 3, 2015
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Well after owning my 93 Fox Mustang for years and finally now deciding to mount firewall ground after years of reading about why it is needed It is finally installed!
So I have been having issues with my 93 Fox Mustang with A/C on at max and headlights on at same time or volts dropping down at idle to the "M" on factory gauge but when I get up to speed it really never goes up to where it needs too be when I first start car.
Yes I have 3G alternator with that big thick power wire and a 93 Cobra overdrive pulley but something never seemed right during summer with all those accessories on at once. I noticed there was a ground wire in back firewall that was not connected to anywhere opposite of firewall. I guess when I had heads removed and replaced my mechanic never put back ground on back of head stud, so after all this time I finally bolted that other side of ground to a nut that is behind cylinder head.
Now I can't say how dumb I was to not hook this up many years ago volts do not drop one bit with everything on AT ALL and my temperature gauge now seems a bit consistent and does not go up or down as much, only issue I am having now are lights flickering a bit. But have read it may now be voltage regulator behind alternator, and I know battery cables are not bad replaced those new and bought factory cables as well.
So if any of you back there experiencing any issues with voltage going up or down too much with all accessories on make sure your grounds are tied down or secured!!
 
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I'm gonna say not the voltage regulator. Put a multimeter on the battery and start the car. Turn everything on (or not) and you should get steady voltage. Mine shows 14.99v and hardly varies. If the regulator is bad it will move around. I have various strange things happen with my factory gauges at times. Sadly I just ignore them when they are acting crazy. I recently replaced the head to firewall ground strap because my temp gauge was acting weird. Didn't help any in my case but it does for most people. If I could afford aftermarket mechanical gauges (water/oil) that would be the answer without a doubt.
 
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Does the flickering change when the engine is revved up? Good catch on the ground, and don't feel stupid about it. Little things like that get over looked all the time.

Kurt
 
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No flickering did not fully go away!
Looking for a ford switch to buy see if that helps.
Cop pulled me over once because flickering lights, gave me warning and never took my car back to Glendale Az