Hi Guys,
I'm looking for the aux tank sending unit in my 1973 F250. The main Tank sending unit is accessible without removing tank. But the rear tank is flanked by the frame. Wondering if anyone has had to replace this sending unit. My gas gauge is reading empty on both main and aux tanks. Thanks for any help.

 

Welcome to FTE.
Being both read empty how do you know you if it is bad sending unit in both tanks, bad wiring, bad switch for each tank or bad gauge?
Is the temperature gauge working? If not then the IVR for the gauges is bad.


What testing have you done to prove that both senders are bad?
A easy test is to ground the gauge sending units to ground.
Flip switch to front tank and ground wire to frame, key on and the gauge should move up to full.
Do the same for the rear tank if the gauge does not move for either you could have bad wiring or bad dash switch and will need to dig deeper.
Dave ----

 

Hey Dave,
Thanks for the info. I have done zero troubleshooting thus far. I inspected the main tank sending unit, reseated the "two prong" connector. Still nothing.
The Aux tank gauge was working not long ago. The main tank hasn't worked since I'v owned the truck. I'm going to do the crawl now and try to short out the main tank 12V send.