sending units going bad?

[rockdogz]

After getting my car back from the body shop, neither the water temp gauge nor the electric radiator fans are working. Both have separate sending units - could they have gone bad just sitting around for a year? It's strange that all other gauges work fine, and when I turn the ignition to accessory I can see the needle of the water temp gauge move so I know it's getting power.

[paul67]

change the sender as the last thing you want is those playing up

[Martin71RS]

Sounds like a ground problem...body shops tend to remove panels and everything attached.......if they painted your car and put the grounds back it could be possible the wire is not contacting metal anymore...

just a thought

Martin

[rockdogz]

Sounds like a ground problem...body shops tend to remove panels and everything attached.......if they painted your car and put the grounds back it could be possible the wire is not contacting metal anymore...

just a thought

Martin

Yeah, I suspected that although all the other gauges seem to be fine. I will have to definitively rule that out though.

[rockdogz]

That makes more sense now that I think about it - if the ground wire from the engine block to the frame/body is gone then that would probably do it... :pat:

[Martin71RS]

Remember it will also affect your ignition and starter then!! Never underestimate the power of good grounds! (you can never have too many)

Martin

[rockdogz]

Well dang, that wasn't it... the ground wire was there. Arrgh.

[rockdogz]

ok well I grounded both wires going to the sending units to the block in turn, and the fans ran and the temp gauge maxed out - so it looks like the sending units...
Is it bad to use teflon pipe joint compound to seal the threads? They did work initially...

[smittys69]

The manufacturers typically say not to use teflon tape as it provides a good seal but it does not ground out against the block (i.e the sending unit threads are not in direct contact with the block). That is how the sending units are actually grounded - via the block.

[rockdogz]

I'm not using teflon tape but a paste.

This problem is still with me... thought I had it solved since I found a ground wire off the ignition, but the gauge and fan are still not working. I'm getting a new sending unit to test, but does anyone have any other suggestions? :nopity:

[rockdogz]

Arrgh, I will (embarassingly) update this for the sake of others who may find this post in a search....

It turns out that they had switched the wires to the two sending units.

:banghead:

[Madspeed]

Heh leave it to bodyshops
They need to learn how to repair cars as well as move metal and spakle pannles
I have seen cars come to me from bodyshops with all sorts of electrical problems 50% caused by the bodyman the other 50% the accident cutting harnesses

[rocketrod]

Arrgh, I will (embarassingly) update this for the sake of others who may find this post in a search....

It turns out that they had switched the wires to the two sending units.

:banghead:
No need to be embarrassed. Just be glad you found the problem and fixed it.