on my 1979 F150, the temp gauge never worked, I need to know what to look for. Please HELP!!!!!!!!!


Joe

 

Well first I'd look to see that the temp sender on the engine has a wire hooked to it. If it's a V8 then look on the front of the intake manifold near the distributor for a fitting screwed into the intake where water would be flowing near the thermastat. Then I'd trace it back to the firewall to see if it has solid insulation and isn't grounding itself w/ bare wire. I believe if you have an inline six that you'd find the water sender on the passenger side of the block nearer the firewall. There is voltage regulator for the instrument cluster pugged into the back of the cluster, but in my experience when it's bad, the gauges read higher than they are suppose to. If the engine bay side looks good, then I guess you need to take a look see on the inside of dash (backside of cluster) there is a master harness that connects a plastic cluster backing w/ the trucks wiring. The plastic backing is etched w/ electrical pathways to the various gauges and lightbulbs as well as that instrument voltage regulator. If all of that seems in order, the perhaps buy a new water temp sender? Or go aftermarket and get either a mechanical sender if you don't mind an umbilical chord that can't be kinked but gives you readings without the truck being on, or an aftermarket sender/eletric gauge that has the actual temp's printed on it.

BBT

 

Remove the wire from the temp sender and touch it to ground. If the guage deflects full scale it is the sender. If it doesn't move it could be the guage, the wire from the guage to the sender or a lack of power to the guage.
9 times out of 10 it is the sender that has failed or the wire is off it.

Sparky