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Temp gauge is asleep!

3K views 14 replies 5 participants last post by  chevyryder26 
#1 ·
Just got my first Caprice, it's a '94 woody wagon.
The temp gauge is not working but it does move.

Here's what it does.
Key in position 1 (off): needle is at about 25%
Key in position 2 (engine off, ign. on): needle is all the way to the left (Cold)
Key in position 3 (starter engaged): needle abruptly goes all the way to the right (Hot)
Once engine starts, needle abruptly goes back all the way to the left again, and does not move from there, unless the engine is turned off again, then it moves about 25% towards hot.

Question: Since the needle does move, is the problem related to the sender switch or the gauge itself?
 
#2 ·
i have this issue with my SS...get it fixed asap..i tried 3 different senders on the engine and none worked so i let it go..then one day the engine stopped because i overheated and it's not a pretty thing. once the new engine is in i'm going to try the OE sender and hope thats the issue but if not, ill be running lines for a dash temp sensor for sure. ill never drive with a broken gauge again
 
#4 · (Edited)
pass side of car near back of engine is an aluminum type cylinder which is a heat shield..i think it's between the rear plug and 2nd one) .pull the heat shield back and the sensor is under there..need a deep socket (maybe plug socket, i forget) and just unscrews but antifreeze pours out so be quick! i've changed this 3x so i'm an expert at it now!

i forget what brand of sensor my parts guy gave me but hope the OE part works. my gauge was tested by my mechanic (jumpering it) and he said the gauge itself works since it was pegged during the test..so i'm assuming has to be the sensor..

this is NOT our cars but it is what the sensor looks like

http://shbox.com/1/temp_sensor2.jpg


part 50 here

http://parts.nalleygmc.com/showAsse...iveline=0&ukey_trimlevel=15486&modelYear=1995
 
#5 ·
There are two Coolant Temp Sensors on the LT1 engine. One is on the pass. side cyl. head where the diagram shows no. 050. The other one is on the water pump at the very front of the engine. One feeds the engine temp. to the PCM and the other feeds the engine temp to the dash coolant temp. gauge. I am sorry I can't remember which does which. Shoebox on the F body version of the LT1 should also show a CTS on the water pump. A long while back, some B body owners were using a three wire coolant temp sensor and rewiring it so that this one sensor would send the same temp. to both the dash gauge and the PCM. The temp, you saw on the gauge was what the PCM saw. Both of the stock CTS were a two wire sensor.
 
#6 ·
dash gauge is the pass side

PCM is the water pump
 
#8 ·
Pass. side temperature "SENDER" only needs one wire. My problems with this were damages to the wire/connector. I believe the item you refer to at the back of the intake is for oil pressure.
 
#14 ·
i'm only speaking from limited experience but my local parts guy tried 3 different ones and none worked..i have a Delphi sitting at home waiting to be installed. i'm assuming AC delco would be good as well.

rockauto has the best parts lookup because for most parts they write OE next to the part and delphi is marked as OE for the gauge sender.
 
#12 ·
The "SENSOR" on the waterpump has absolutely nothing to do with the temp. gauge on the inst. panel. It gets it's signal from a "SENDER" on the pass. side head. There exist multiple threads on this issue already, and some of them are quite extensive in their coverage of this issue.
 
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