I just put a SR5 Cluster set from a 84 into my 87. I ran a wire for the Tach and it works have not changed the Oil pressure sender yet so I just left it unplugged for now. My water temp gauge jumps to the top once the ignition is turned on and stays there after it has been started. The water temp seemed to work with the original cluster so I am stumped to what is going on. i tried to search for the answer and was unable to locate and useful posts. Any help would be appreciated.

 

Usually when a gauge maxes out like that, it indicates a short somewhere . I'd check all your connections on the plugs on the cluster to make sure there is not a bent tab or something . Coincidence... maybe the sender just decided to take a crap at the time . I've had stranger 'stuff' happen .

 

Ok, so when I started it this morning it stayed at cold for about 30 seconds and then gradually pinned itself at hot, bad temp sensor?

 

Are the temp sensors the same part # for 84 and 87 ?????

 

Yes, they are the same.

 

Unless there is some wire getting pinched somewhere that is shorting out. Disconnect the sensor and run a jumper between the two wires and see how the gauge responds .

 

I put in a new sensor today and it still acts the same so tomorrow I will run a jumper from the sensor straight to the gauge and see what happens.

 

Hmmm... love it when problems like this pop up !! Where did you get your SR5 cluster from and how much did you pay ? Looking to do mine, but some of these clowns on ebay ......

 

I got it for $30 off a Craigslist ad, guy was parting out a 84 SR5 Longbed.

 

So, after running a jumper straight from the sensor to the gauge and still getting the same results I ohmed out the gauge, gauge is bad...