wiring question

[jdepiero]

Hi Guys,
first, a brief history. I purchased a 1955 PW late summer 2015. It ran but nothing electrical worked. It was converted to 12volt at one time but the wiring was all the old cotton covered wire that most was bare and had shorted out from touching other wires to body parts. I re-wired all with a lot of help from this forum and using the searches. I finally fired it up today.
All works with the exception of the fuel gage and the panel lights.
First the fuel gauge. I replaced the tank and sending unit from VPM. I also just purchased the fuel gage from VPM. With the take empty the fuel gauge reads 1/2 full after powering up? Why?
Now the panel lights; the panel lights work with the headlight switch in the parking light position but when the headlight switch is in the headlight position the panel lights go out. The headlight switch is still the original.
After working with the schematics for over 3 months I am fried myself!
Joe

[Kaegi]

I would call whoever you got the gauge and sending unit from and tell them the problem. on the panel lights you have the panel light power wired hooked up to the cowl light post and it needs to be hooked up to the tail light post on headlight sw.

[jdepiero]

you are correct. I had the wires reversed. I looked at this 100 times and did not see it.
thanks

[Kaegi]

all old vehicles before about the mid 60s the front parking lights go off when the headlights come on. I suppose they thought why waste the life of front parking lights?

[Doc Dave]

I bought a new sending unit from VPW many years ago.
These are, I think, off shore made repro units.
The reading I got from it was off by at least a 1/4 tank.
I could not figure it out so sent it, along with my broken OEM one, in to a gauge shop.
They told me the VPW one was not the right resistance for a dodge truck I guess the suPPLier that made them goofed.
The shop fixed my old one and then no worries, except I did have to fashion a little pigtail of wire from the arm to the base to ensure a good ground. This is covered in the forum archives.

[jdepiero]

I plan on calling VPW in the A.M. but what Doc says unfortunately seems to make sense

[Doc Dave]

Joe,
Depending on what VPW says - maybe they are getting them now from somewhere else - you might end up sending it in to have it tested at a shop. Also I think, though, the shop manual might have a procedure where a person could bench test it themselves, not sure.
I sent the VPW one into the John wolf company in Ohio - the charge for testing it was not much.
Do you have The original non working one? If so send that to the gauge shop.

[53Crusher]

This was one of the most frustrating areas of my rebuild for me. Like you, I did a complete re-wire from 6V to 12V and had everything working but my fuel gauge. Throughout this whole process, I used a variety of 12V to 6V reducers. Not knowing if original gauge and sender still worked, I replaced the gauge with a used one. No luck. Bought two new aftermarket senders from different suppliers. No luck. Found NOS fuel gauge. No luck. Found NOS sender..... bingo- everything started to work again. In retrospect, the original gauge had probably been fried from the 12 volt conversion. Original sender was very worn and in need of replacement.

Biggest problem I found was one vendor's fuel sender had a resistance range of about 40 - 120 while the other one was 0 - 80 ohms. It's been several years now, but if I am remembering correctly my 53 needed a 0 -80 range for the gauge it had. Anything else will give you false readings.

[jdepiero]

I spoke to VPW today and they told me the sender they sold me should read 33-240 ohms. if it does not I "got a bad one". I just got home so I did not get a chance to check it.
I got to thinking today about the ground. I have the sending unit grounded to the frame, but how many strap ground should the be on the truck? I only have one, from the frame to the clutch housing

[Doc Dave]

Joe,
I have many grounds on my truck:
Engine to frame
Cab to frame
Bed to frame
sender to frame
This has helped me avoid a lot of electrical gremlins.
Do you have a shop manual for your year of PW? It should say in there, I think, what the sender resistance should be. No offense to VPW, but I would see what the manual says and if the one they sold you is different, I would question that if it did not work.
I think in the archives of this website or Joe Cimoch's forum archives, also what the resistance range should be.