“New” WBX 2.1, temp gauge at max without engine running

[AlfromNH]

First start of my winter project. 2.1 wbx with new coolant sensors, pipes, water pump, etc.
Turn the key and the temp gauge slowly raises to max, even without the engine running. There are 2 temp sensors on the tstat housing, blue and black. Which one goes where? The wiring harness has a blue and black connector, so that part seems hard to mess up.

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‘88 2wd Auto Westy project

[kamzcab86]

Black one is gauge sender. Blue one is the Temp II sender for the Digifant ECU. Doesn't matter which port they sit in, but my Temp II is on the driver's side.
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~Kamz
1986 Cabriolet: www.Cabby-Info.com
1990 Vanagon Westfalia: Old Blue's Blog
2016 Golf GTI S
"Real knowledge is to know the extent of one's ignorance." - 孔子

[AlfromNH]

A response in one minute, I love thesamba!

Thanks for the reply, I’m out of shop time for today but I’ll follow up tomorrow.

Al
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‘88 2wd Auto Westy project

[AlfromNH]

I’ve confirmed the black connector(temp gauge) is plugged into the black sensor, and blue into blue.
After sitting overnight, the temp gauge needle doesn’t move when turning the key on, it stays in the “cold” position. I’ve confirmed:

~10v at the connector
When I jumper the 2 pins on the connector the needle goes to max
When I put a 100 ohm resistor across the pins, the gauge goes to about 1/4(see pic). Does that seems right, is there a spec for resistance vs needle position?

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‘88 2wd Auto Westy project

[AlfromNH]

Answering my own post…

I found a thread on resistance values for testing the gauge and this response to 100 ohms looks about right. I’m thinking I have a bad(brand new) sensor.
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‘88 2wd Auto Westy project

[AlfromNH]

Can confirm it was the sensor, replaced it with an old one I had and the gauge is behaving normally.
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‘88 2wd Auto Westy project

[bobhill8]

Nice work Al. Glad it was a simple fix
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1986 Westy
1971 Squareback

[AlfromNH]

Thanks Bob, I’m really psyched to have it on the road!
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‘88 2wd Auto Westy project