Technical Electrical Things

[m0rg]

Hi All

I have a couple of minor electrical things to sort out on my new 750 and was wondering people's thoughts on the following

First off is the cooling temp reading on the dash isnt reading correctly

Ignition off it reads 0 as it should
Ignition on it reads 90
Engine up to temp shows 125
Cable disconnected from sensor reads 90
Cable grounded ends with the guages showing past the highest reading roughly 140

I'm guessing it's shorting to ground somewhere

Secondly not sure radiator fan is coming on , I have tried a different fan unit and thermal switch . Though it could just not be getting hot enough but cant tell due to issue 1

Does anyone have a basic wiring diagram for both

Many Thanks
Matt

 

[Freebo]

I have this issue and believe it to be related to the dial itself, fan comes on fine if it goes above 125 so suspect the spring or something in the dial has gone weak. I replaced the sensor, wiring etc only thing I've not swapped is the dial itself.

 

[m0rg]

Thank you, i will pull the gauge out of my other car and try it this weekend and let you know how i get on

 

[Sjvarley]

If you wish to check the fan unplug the thermostat mounted on the radiator. Link the 2 pins with a shorting wire the fan will start proving the circuit . If the engine is getting ing too hot with no fan the thermostat is suspect
To check the fan unplug the fan and apply 12v across The fan plug ,fan will start.
To check the fan in place short one leg of the thermostat to negative / earth by unplugging the plug on the stat as the thermostat is negative switched to cut down on the current through it. Then try the other leg . That may also show a poor earth , if the fan starts

 

[m0rg]

Thank you , seems like the fan is working and the thermal switch too , onto the guage this weekend

 

[Sjvarley]

Gauge. Could be a bad engine earth. On the sender unit. Try cleaning up the spade crimp. Ensuring it is a tight fit. Sender unit works by The resistance getting less as the temperature increases. Any additions resistance will alter the needle position. IE read cooler