Coolant temp sensor 1990 VW Jetta 

Oh have you tried switiching the connectors around so black on blue and blue on black could work. Is your thermostat working and what does your temperature gauge get up too ?

I've got a golf 2 1.6 and I have the black sensor and blue sensor, black one is all plugged in but the blue sensor doesnt have any wires to be plugged in. What is the black sensor and how important is it that I have the blue sensor plugged in

do you know what your problem was?

what problem u got there ? can I help?

my 89 jetta gl is doing the same thing but my blue and black sensors are switched in the housing, and when the blue is plugged in it idles fine but misfire when running and when its plugged it it runs fine amd idles at 2k rpm constanly and overheats when sitting not when driving and theres airflow. any ideas?

When i turn the coolant sensor the idle its on 1000 when it is of it on 900 does he work or he is bad

Check the timing points

Hi there , just wanted to know what the blue and black sensors represent ? Thanks for the upload also, my Gti has and idle problem.

Still haven't figured it out? I'm having the same problem!

Supiste que era el problema

damn i hv the same problem as well what can i do. i even used mk3 temp sensor n still same problem

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