1989 Volkswagen Jetta coolant temp gauge inop

Tiny
FRICKER
  • MEMBER
  • 1989 VOLKSWAGEN JETTA
Engine Cooling problem
1989 Volkswagen Jetta 4 cyl Front Wheel Drive Manual 250K miles

guys,
replaced Temp sensor w/new unit and gauge inop still. What else could be problem. Gauge show's full cold. Had similiar problems years ago and gauge went full hot. New sensor and works fine till now.

Having same problem with fuel tank gauge-shows empty.
btw- installed rebuilt engine and want these gauges to work well- h2o temp inop caused orginial engine to seize up-throw a rod.

any ideas
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Saturday, March 28th, 2009 AT 5:32 PM

8 Replies

Tiny
DR LOOT
  • EXPERT
I need to know a little bit more before I can help you diagnose the problem, when you turn the key on does the warning light flashed on the temperature gauge? You said you replaced the temperature sending unit, which one did you replace? There is a primary and a secondary temperature sending unit, answer my questions and get back to me.
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Sunday, March 29th, 2009 AT 10:49 AM
Tiny
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Good answer.
I replaced I guess the primary sensor. Will have to check if red lite comes on or not.

Unit I changes was blue in color and rounded metal bottom. On engine comp- its' closest to engine in it's frp casing.
Will let you know this evening if Red lite comes on. Thanks.
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Sunday, March 29th, 2009 AT 11:10 AM
Tiny
DR LOOT
  • EXPERT
There should be two sensors on the thermostat housing, or another one at the side of the head on top of a transmission.
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Sunday, March 29th, 2009 AT 11:18 AM
Tiny
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It must be beside the other sensor, this vw is manual transmission. Let you know in couple hours.
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Sunday, March 29th, 2009 AT 2:33 PM
Tiny
DR LOOT
  • EXPERT
OK.
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Sunday, March 29th, 2009 AT 3:16 PM
Tiny
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Just got back and red lite does flash. Swap'd old aft sensor for forward sensor to see if it works? Maybe is alll I can say.
Going to get new forward sensor and go from there.

Any suggestions are welcome? Oh, and need metal clips for various electronic connections - Ilde/cold start solenoid, etc. Ideas where to ge them?
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Sunday, March 29th, 2009 AT 6:18 PM
Tiny
DR LOOT
  • EXPERT
I believe that you may have the wires mixed up, considering you had the engine replaced, it is very easy to do that, if you need a wiring diagram I can probably get that for you, let me know. About the clips you are looking for, the only parts store I know that has a good selection of clips is Napa, or you may have to go to your local junkyard.
Because the light is flashing I don't think its cluster problems, the only way to check to make sure you have the right wire is to put to ground and if the gauge goes all the way to hot, that means you've got the right wire, I will address your fuel gauge problem after we fix your cooling problem.
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Sunday, March 29th, 2009 AT 11:07 PM
Tiny
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Dr hoot,
Thanks for info. It may be 2nd sensor is "bad", had 1st sensor go bad yrs ago and 'temp' gauge goes full 'hot'.
The reason for new engine is old 1 blew-water pump failed and gauge wasn't working-my oldest son was driving it.

Got the 2nd sensor in hand and go to parts store for replacement to insert. Swapped primary sensors and gauge seemed to move a bit-don't want to blow another engine=$$$
thanks!
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Monday, March 30th, 2009 AT 9:49 AM

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