Temp light "system" question

[llong66]

Hello all! as my title says I am having an issue with my temp or over heat light.
I put system in quotes because after looking through the TMs, I see nothing to it but the sensor and light.
My truck,an 85 M1008, will not light the light when I first put the ing. switch in the run position. I have checked/switched
bulbs and sockets all with no results. Is it a fair guess that the sensor is bad and should just be replaced? I can't seem
to find any real trouble shooting for it, and as I said from what I see what else could it be? Any suggestions?

Thanks,
Greg

 

[Drock]

I can't help you with the light, sorry. But I would highly recommend installing ah temp gauge and forget about the light.

 

[TGP (IL)]

The Temp light only lights while cranking, and only in the run position when overheated.
I couldn't find the trouble shoot other than low coolant light myself.
You could remove the green wire from the sensor on the front drivers side head and ground it
With the key on and see if it lights.
If it does replace sensor.
If it don't light, you will need to trace the wiring and look at the bulb connection.
Tom

 

[Skinny]

That's a good troubleshooting tip!

I vote for removing that temp sender for the dummy light and putting a temp gauge in. I really like my temp gauge especially when hauling lots of weight or when its super hot down here. Lot's of piece o' mind comes from looking down at that needle

 

[Drock]

Agree I just installed ah gauge ah month ago and found I was running hot do to ah sticky thermostat. The light never came on! I guess the light is only good for telling you all **** has broken loose. With the gauge you can monitor the temp and know your having ah problem ,BEFORE the motor melts down.

 

[Warthog]

Why not leave the light and add a gauge. That way if you forget to look at the gauge the light will warn you of danger.

 

[llong66]

I have both a gauge and light. I like the idea of both. On a vehicle I had years ago, it had both light and gauge, I popped an oil line and the light caught my eye before the gauge, got it shut down before any damage.

 

[richingalveston]

I rewired my dash using a civy cluster so I have all gauges. I kept the light sensors and ran all of the warning lights into the check engine light. And yes a light will catch your attention faster than the gauge. The gauge helps to determine how bad the problem is but without the light you almost never check the gauge until it is to late.

 

[Skinny]

You light guys would crash a plane pretty quick...head on a swivel and scan your gauges

 

[CUCVLOVER]

 

[Drock]

You light guys would crash a plane pretty quick...head on a swivel and scan your gauges

AGREE!! I guess because I've always driven "project cars" , and driven them like I stole them. My eye's are constantly scanning the gauges, and mirrors. Those 30 year old "warning" lights , IF THEY WORK?? Tend to only come on after everything's gone sideways.

 

[Skinny]

I don't even think gauges on new cars are even accurate. Since everything is interpreted by the engine computer then sent over a body network to a gauge module (your cluster), they are typically programmed to read dead nuts center until something bad has happened. Of course that is on a decent quality vehicle. Has anyone ever driven a Chevy Express Van? Those gauges all point in opposite directions if things are going good. Yeah...that isn't easy to scan

 

[cpf240]

We had a '94 Ford Exploder and the oil pressure gauge *always* gave the same reading if the engine was running, no matter what the RPMs were. Turns out Ford got tired of people complaining that the oil pressure would drop when they came to a stop, and then go back up again when they resumed driving. So, Ford put in a real oil pressure gauge with a resistor on the back of it connected to an idiot light switch on the engine. Easy to fix though, jumper the resistor and put in a real oil pressure sender.

 

[llong66]

Well, I finally got around to fiddling with this issue more, I puled the cluster and indeed the trace had partially pulled aray and was not making contact. I got it back in place, tested it out on the bench and it worked fine. Put everything back together and still no joy. However, now when I ground the connection at the sensor the light will light, so I am guesing as stated above, I just need to replace the temp sensor now?

Thanks,
Greg

 

[Mg84648]

You light guys would crash a plane pretty quick...head on a swivel and scan your gauges

Actually with the advance of more sophisticated and complex aircraft and thier associated systems, aircraft manufacturers began installing master caution and warning annunciators on cockpit glare shields in line of sight of the pilots to alert them to look down at a malfunctioning system. Task saturation during takeoffs and landings were causing pilots to miss malfunctions they would otherwise catch during thier instrument "scan".
I vote for an "idiot" light AND gauge

Sorry I didn't help with your problem.

 

[llong66]

Coolant temp sender/switch part number

Hello everyone. I am wondering if anyone has the part number for the engine temp switch that controls the idiot light in the dash. I have looked through the TMs and they go into changing the unit out, but no part No. or NSN listed that I can find. The units that the local big box stores all have must be the sender for a gauge as they have two terminals as oppose to just one. I have looked various places online and there are several units pictured, but I am unsure which is the correct one and the $$ can vary significantly.

Thanks for your help,
Greg.

 

[porkysplace]

The parts TM's end in -P have the part GM part numbers.
TM9-2320-289-20P.pdf
TM9-2320-289-20P Unit maintenance and depot maintenance parts and special tool lists for CUCV
TM9-2320-289-34p.pdf
TM9-2320-289-34P Direct support and general support maintenance repair parts and special tools lists.
[h=1]GM CUCV Parts and Illustration Catalog 52D[/h]

 

[llong66]

Thank you very much!

 

[doghead]

Merged your threads.