[DeTomaso] temp gauge sending unit.

[JDeRyke at aol.com]

In a message dated 10/18/10 10:44:46 AM, boyd411 at gmail.com writes:

> Do the sending units go bad? Is there a way to test the sending unit. If 
> I replace it is there a replacement available through NAPA or other 
> national chain auto parts stores?
> 
Yes to all the above. What sometimes happens is the wire falls off the 
gauge so check that in the console before doing anything rash. Then check the 
wire itself for continuity- there's a multi-connector near the firewall that 
sometimes needs to be sprayed out with Radio Shack Contact Cleaner. And the 
ring-loop on the wire sometimes cracks from vibration, or someone really 
tightens the sender top-nut without backing up the bottom nut and separates the 
sending connector inside. Finally, replacement senders are cheap at Autozone 
or NAPA; just ask for one for a '71 Mustang or Fairlane. 
Its a 1-wire sender that depends on a block ground and some have used 
excessive amounts of teflon pipe tape when screwing it into the block, and found 
they'd electrically isolated the sender from the block so it gave no reading 
without a separate ground.... 1-1/2   turns of tape is enough for the pipe 
threads. Do NOT put the sender in the plugged extra hole in the water pump; 
cavitation inside the pump will give erroneous readings and erode the brass 
sender over time. Besides, it interferes with alternator belt adjustment. 
Good luck- J Deryke