coolant temp gauge help 87 K5

[brans87]

My 87 K5 had a aftermarket set of cheap 3 gauges under the dash when I got it, after cleaning up previous owners wiring removing non stock stuff I hooked all gauges back up Factory style. I have a new coolant sensors and show power, ground when gauge is hooked up but the driver side pole makes the gauge shot up to over 240 and stay pegged. Is there a way to test? I checked when had whole cluster out and printed circuit board seemed to be ok with my meter. Like coolant gauge to work for one and looking into installing windstar coolant fans I picked up today. I never trust a Ford part so my Chevy gauge needs to work. Thanks in advance.

 

[USSkoval]

So what exactly are you hooking up to peg the temp gauge? Is it the green sending wire to the temp sender in the driver side cylinder head?

If so, it sounds like the temp sender is faulty. Is that one that you replaced?

 

[brans87]

yes it is in the head with green wire attached. If you ground green wire you can get temp gauge to peg also. When you remove the gauge itself from the cluster and go to reinstall it if you play around with how it installs second it leg touches the clip far left side it goes to 240 up on gauge. From what i know looking at the cluster with gauge removed top clip ground, right is power and left must be to green wire.

 

[dyeager535]

Pull the whole cluster out and follow the traces. 1987 printed circuit "board" may have the various traces labeled. At least 1990-1991 they did, makes it a lot easier/quicker/positive than the earlier ones.

Can you tell by pictures here which gauge I marked? It's either oil or temp, but you'd want to verify as they are "pinned" differently. http://coloradok5.com/forums/showthread.php?t=304941

The cluster connector is garbage, as is the PCB, thus why I hardwired. In most cases they work ok, but when they don't, they are annoying.

You have one sensor and one sending unit. The temp sending unit is one wire, the two wire is the CTS and has no bearing on the gauge, which I believe you understand, but want to make clear.