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Temp gauge not working 89 350

S

steve smith

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I cannot get my temp gauge to

I cannot get my temp gauge to work on my 89 merc 350 I have changed the sensor that is on the block (didn't work)I changed out the gauge and this did not solve the problem either I checked the connectivity of the wire from sensor to gauge with a meter and this was fine so I am not sure what to chek next
thanks for your help
steve
 
"Check for resistance (ohm

"Check for resistance (ohms) between the center tap of the sending unit (with the wire to the guage disconnected) and ground on the engine block. You should get a reistance value which will change depending on temperature. If you get an infinate reading, it's probably not grounded properly. If you used any kind of thread sealant, that may be the problem.
Other things you can check is power to the gauge and make sure the wire between the guage and sending unit isn't grounded somewhere."
 
the sensor does not have any t

the sensor does not have any type of sealant or tape on it. last summer the impeller broke and the boat over heated. since that time I can not get a reading on the gauge. I also thought that it could be the wire but I ran a new wire direct from the sensor to the gauge and still nothing. the light on the gauge comes on just no temp reading
thanks again
steve
 
"have not checked resistance y

"have not checked resistance yet, and probally will not have a chance until this weekend
thanks
steve"
 
"Steve,

Let's make thi

"Steve,

Let's make this simple. Confirm that you have <font color=""ff0000"">12V+</font> and 12V- at the proper terminals on the gage by testing for power at the gage terminals. Gage should be at rest. Jump across the "SNDR" and 12V- terminals on the back of the gage. The needle should peg. If it does not, the gage is bad. If it does, the problem is the signal from the sender. Now short the sender terminal against ground (12-) back at the engine. If the needle pegs, the sender is bad or is not grounded. If it does not, you have an open circuit between the sender and the gage. It's that simple. Knowing that the motor was overheated, I would be suspicious of the engine harness in the area of the exhaust manifolds, but don't think that just because you replaced the gage and sender, that neither one can be the problem.

Good luck
Rick"
 
thanks for the info I'll p

thanks for the info I'll play with it this weekend and see what I come up with. once again thank you
steve
 
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