temperature sender needs a ground?

[luc8421]

Hey guys, ever since I got my bike a year and a half ago, the temperature sensor hasn't worked. the gauge works, I can ground the wire from the gauge and it'll spike all the way like the mannual says to test. With this in mind, I'm assuming the sender itself is at fault.

However while looking at it the other day, I noticed the previous owner seemed to use some kind of silicone or teflon tape to seal it in the case. Does the sender need a good ground to the case to operate? it's sealed nicely and not leaking, so I don't want to disturb it if I don't have to

[hungryman]

Typically they are grounded through the case of the temp sensor.

[bwringer]

Temperature sensor?

[luc8421]

Yeah, there's a temperature sensor, sorry if I'm using the wrong term, perhaps temperature sender is more accurate a description. It's the bolt with the threaded shaft coming out the top of it for a single wire. it's screwed in right behind the starter motor cover, in the middle of the case

[hungryman]

Yeah, there's a temperature sensor, sorry if I'm using the wrong term, perhaps temperature sender is more accurate a description. It's the bolt with the threaded shaft coming out the top of it for a single wire. it's screwed in right behind the starter motor cover, in the middle of the case

Probably an oil pressure sending unit. Same applies, the case is the ground. If there is one wire, the case must be the ground.

[SqDancerLynn1]

Some of them had an oil temp gauge

[Road_Clam]

Hey guys, ever since I got my bike a year and a half ago, the temperature sensor hasn't worked. the gauge works, I can ground the wire from the gauge and it'll spike all the way like the mannual says to test. With this in mind, I'm assuming the sender itself is at fault.

However while looking at it the other day, I noticed the previous owner seemed to use some kind of silicone or teflon tape to seal it in the case. Does the sender need a good ground to the case to operate? it's sealed nicely and not leaking, so I don't want to disturb it if I don't have to

Temp or oil guage sensors do not use a "ground". The sensor reads varying ohm resistance output from varied temps. This ohm output is read by the the guage. It's very common practice to taflon tape the NPT threads to minimise leakage. You simply have a faulty sending unit. One possible cheap fix is to pull the sending unit and simply clean the brass nipple inside, sometimes the build up crud, and do not allow a proper temp reading (this is far more common on anti freeze type cooling systems than on oil cooled systems). If I remember elerctical "theory" in trade school, this is how guage sensors work, if I have it wrong, jump in an correct me.
Rich

[blo]

Temperature sensors of this type works by measuring the resistance over a PTC element (US: RTD) this is a metal/alloy which alters it's resistance in relation to temperature. They are usually grounded to earth thru the chassis (one wire type). It is vital that this chassis connections (e.g the threads) is good. Any extra resistanse due to corrotion, sealing tape or such will cause an offset to temperature, or lead to the unit not working at all.

That said, it is not uncommon for these units to short out, burn out internally or othervise fail.
To check:
- unscrew unit
- using a voltmeter set to Ohm measure the resistanse between chassis/threads and lead / wire
- 0 Ohm => defective (shorted)
- M Ohm or inf. Ohm => defective (burnt out)

anything inbetween is ok.

[hungryman]

Temp or oil guage sensors do not use a "ground". The sensor reads varying ohm resistance output from varied temps. This ohm output is read by the the guage. It's very common practice to taflon tape the NPT threads to minimise leakage. You simply have a faulty sending unit. One possible cheap fix is to pull the sending unit and simply clean the brass nipple inside, sometimes the build up crud, and do not allow a proper temp reading (this is far more common on anti freeze type cooling systems than on oil cooled systems). If I remember elerctical "theory" in trade school, this is how guage sensors work, if I have it wrong, jump in an correct me.
Rich

Everything has a ground, either through the case or with an external wire. If you don't believe me try your one-wire sensor held in your hand.

[Road_Clam]

Everything has a ground, either through the case or with an external wire. If you don't believe me try your one-wire sensor held in your hand.

Not the factory designed GS R/R system!!!!! Thats why they fry themselves! LOL