Brown temp sensor wiring

[mcspike]

Hello

I'm going to be fitting an M44 into my E30 but will have to use the M40/2 brown temp sensor for the gauge cluster.

Any pointers for the wiring before i start digging?

Cheers

[Brianmoooore]

Cut the brown/red away from the four pin M44 sensor plug, and splice on a piece of single core wire with an E30 brown temp. sensor plug on the end of it, long enough to reach the brown sensor fitted to the M44.

[jmc330i]

As Brian says, but there is nowhere to conveniently fit the brown sensor on an M44. Mine is currently in the top rad hose which isn't ideal.

I left the M44 wiring alone and ran a new wire from the C101 to the E30 brown sensor because someone told me they could possibly get the M44 sensor to work the E30 guage..... Im still waiting 2yrs on
Another option was to look at fitting the E36 guage to the E30 cluster, but I don't know if that's even possible and it's not something I've personally looked at.

[Brianmoooore]

someone told me they could possibly get the M44 sensor to work the E30 guage..... Im still waiting 2yrs on

I've never looked into this, but it should be relatively simple. Both the e30 and E36 sensors are simple NTC resistors, but have different resistance ranges. I'm familiar with the normal working range of the E30 sensor (~ 4k ohms to 300 ohms), but have no idea what the equivalent is for the gauge part of the E36 sensor.
Should be easy enough to arrange a transistor as an emitter follower to make the E30 gauge read about right at the engine working temperature - we're not looking for a totally accurate, calibrated gauge over the whole scale.

[mcspike]

Brilliant, between this and the wiki I have a plan!

As I've wired in the temp gauge feed from the M44 to my C101 plug I'll just cut into the wiring near the M44 temp sensor and extend that to the thermostat housing which I think is where the brown sensor will go.

Thanks.