temp sending unit

[midnight rambler]

I need to replace the stock temp sending unit on my 74 sbc 350. Dosent seem to be working. What is the best one to purchace or does it matter ? Its a TS6. how do i trouble shoot this to determin if its the sending unoit or the gauge ? also i noticed there another wire that runs along side in the harness might be tan in color any idea what this was used for ? Thanks

[willett]

I believe the temp sender changes resistance as the temp changes, stick a multimeter on there and monitor it while idling from cold. If the value changes move
Down the line and do continuity checks to the gauge. If the circuit is open or resistance doesn't change it's the sender..

[ray_mcavoy]

Originally Posted by willett

I believe the temp sender changes resistance as the temp changes, stick a multimeter on there and monitor it while idling from cold.

That is correct. The sending unit resistance should decrease as the engine temperature increases.

A "quick check" of the gague & wiring can be done by temporarily grounding the sending unit wire. Turn the key on and observe the gauge. It should peg to the full hot position (or a bit beyond) if the gauge & wiring are okay.

The nearby tan wire is probably for an idle stop solenoid on the carburetor ... does it have a single terminal connector on the end?

[midnight rambler]

single connetor terminal on the sending unit...also the tan wire is a single connetor terminal, im running a 1902 edelbrock on it