Change in voltage

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John Collins

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When I use my break pedal as a ground, there’s a voltage drop of about 1.7. If I ground anywhere else, testing the same wire(s), it’s consistent every place else that I use as a ground. I don’t see any wires touching it. Seems odd to me. Any help is appreciated.
 
You need to explain more about just what you are doing, but there is never a reason to use a brake pedal as a ground, because, well,.............it's not.......the brake pedal I mean......It's not grounded, I mean

THINK about it. The brake pedal is a separate piece, with a bushing/ bearing that might/ should have some lube in there, resting up against a stop, pushed there by a spring, connected to the master through a push rod with loose connections on both ends

Did anything I mention suggest a good tight clean solid ground?
 
In fact it gets worse............

Another annoying story from the old days. "Some time in the 70's--80's" a customer came into the parts store he has about a 62ish Ford pickup. Bought some lamp enclosures and some 4537 100W landing lights. Got them all wired up with a continuous duty solenoid and THEY WILL NOT WORK. Had them mounted and grounded to the bumper on his Ford pu. The bumper was rusty under the bolts TO THE FRAME and the bumper was not grounding. Simple.
 
That’s like using your Kickdown linkage for a ground. LOL. It’s a moving part not a solid connection to the body.
 
Thank you. I normally use the firewall when working under the dash, but it was convenient and made me scratch my head... I thought it was very odd that it dropped by 1.7 every time when testing, so I thought I’d ask. Thank you guys again.
 
Should be a ground from steering column to dash I use for my under dash gauges for ground. That's on a 68 Dart. Don't know what your working on.
 
Word. It’s a ‘73 sport. I have the same ground as well... I used the brake pedal to ground my volt meter while testing some wires. Just thought it was strange that the other 10 points I tested for a ground after seeing the drop, had the same consistent reading.
 
The pedal is probably 'grounding' through the push rod/master cyl connection, a poor connection & showing up with the voltage drop you were getting.
 
Bewy said:
The pedal is probably 'grounding' through the push rod/master cyl connection, a poor connection & showing up with the voltage drop you were getting.
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Thank you. It makes sense now. I was knee deep in fixing an electrical problem that’s been plaguing me since I bought this car. After reading the posts here and feeling like an idiot, I checked my accelerator pedal and it had a similar result. It felt good though to knock it off the list of possibilities and move on. I ended up finding the last gremlin(there were many many issues I’ve addressed. In retrospect, I should’ve just bought a re pop harness) in my electrical yesterday. After 4 f’n months of slowly struggling. Lol.
 
John Collins said:
Thank you. It makes sense now. I was knee deep in fixing an electrical problem that’s been plaguing me since I bought this car. After reading the posts here and feeling like an idiot, I checked my accelerator pedal and it had a similar result. It felt good though to knock it off the list of possibilities and move on. I ended up finding the last gremlin(there were many many issues I’ve addressed. In retrospect, I should’ve just bought a re pop harness) in my electrical yesterday. After 4 f’n months of slowly struggling. Lol.
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I agree. If I do another old car the first thing I will do is buy all the harnesses.
 
When I was a kid my older friend used a piece of plywood and tacked up his 1970 Truck harness . I helped him unravel all the tape and he systematically replaced each wire and terminal . Then rewrapped it . Looked similar to this. It wasn't really bad . He just took his time and did it here and there until he was finished.

wireharness board.jpg
 
Kendog 170 said:
When I was a kid my older friend used a piece of plywood and tacked up his 1970 Truck harness . I helped him unravel all the tape and he systematically replaced each wire and terminal . Then rewrapped it . Looked similar to this. It wasn't really bad . He just took his time and did it here and there until he was finished.

View attachment 1715730534
Click to expand...

That’s really smart. I was about to pull the entire harness and use a 6’ work table, but finally found the final(hopefully. Lol) issue. I’m going to save this pic though. When I change my engine out, I’m going to go through the wiring again and if I don’t buy a new engine harness, this pic will be helpful. Thank you!
 
That pic was just from the internet. But he used finish nails and bread ties to hold in place.(whatever works) The idea is to maintain the correct shape and length so it goes back in the vehicle without stressing the harness twisting and bending.
 
Kendog 170 said:
When I was a kid my older friend used a piece of plywood and tacked up his 1970 Truck harness . I helped him unravel all the tape and he systematically replaced each wire and terminal . Then rewrapped it . Looked similar to this. It wasn't really bad . He just took his time and did it here and there until he was finished.

View attachment 1715730534
Click to expand...

We used to rewire cars with spools of wire when I was a teenager. Back then I had lots of time and no money. Later in life I find it has reversed. Seem like I have less time and am willing to trade some money for time. It all comes down to a personal decision on everyone’s part I guess.
 
I have every color in the rainbow and then some... My neighbor is retired and has a crate filled with spools and he gave me free reign to use what I needed for this project and anything else I need in the future. About 50% of my engine harness is all new wiring now. After all that work, I almost gave up. Glad I didn’t... I just got tired of learning. Lol.
 
Wiring can be one of the most frustrating things you can do for a novice. The interesting thing is that once you get past the learning curve it is really one of the easiest things you can do on a car. Unlike plumbing, it doesn’t leak and and if you kink it, it still works!
 
Mike69cuda said:
Wiring can be one of the most frustrating things you can do for a novice. The interesting thing is that once you get past the learning curve it is really one of the easiest things you can do on a car. Unlike plumbing, it doesn’t leak and and if you kink it, it still works!
Click to expand...

When I wired my Hardtop I was dreading it. I drew everything out on paper, took my time, and by the time I was finished I actually was enjoying it. Felt great when it all worked too lol .
 
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