Hi,
I'm back in the Cherokee game from about a 10 year break. I am curious if anybody knows what temperature will trigger the "check gauges" light to come on for the engine and transmission? My wife was going to drive the XJ and I wanted a dummy light to help at her in case something comes up. I would love to rely on the factory check gauges light, but if I have to put some sending units and warning lights in myself then oh well. The biggest concern is that besides having the check gauges light come on while driving my old 97 XJ I have no experience or idea what engine or transmission temp will make that thing glow.

Thanks!

 

I don't think there's a temp sensor for the transmission at all, not even as an input signal for the ECU.

 

On my 98, my "Check Gauges" light came on just as my coolant temp gauge pegged out at 260 just a couple of weeks ago. Moments prior, it had crept up to around 225 just before it pegged out on me and light didn't come on until it maxed. Don't think there is a transmission temp sensor unless you have a transmission cooler, and even then probably only if you installed one yourself.

 

Ahh yes yes. I am mistaking my tundra for the jeep. The tundra had two trans temp sensors with a warning light. The jeep jeep probably has no trans temp sensors.
I was thinking when I saw my check gauges light on my 97 XJ it was when the whole cluster was acting weird and the temp went from normal to pegged out and back again. If it doesn't come on until near 260 then I better get a temperature sender and a light because I don't want my wife to flog the thing from light to light with the AC on thinking everything is fine until it's really too late anyway.

I'm thinking maybe I get a temperature sender that kicks in at 215 or 220* and wire that to a light and maybe even a flasher for extra emphasis. At what temperature would you guys want to be notified that things were getting a little too toasty? I mean if someone borrowed your Jeep, what temperature would you want them to get the blinking light that says "pull over, pop, the hood, and blast that heat"? (Or whatever you do besides cursing when your vehicle does something potentially dangerous)

 

Probably 225F or so for a warning light to come on.

 

Yes, 225* is about where I get concerned. The Grand Cherokee has a trans overheat light, but I don't believe the XJ does. The "check gauges" lights come on only after the gauges peg out, either at Zero or Top. The electric fan cycles between 195* and 215* so 225* would be the danger point. I've been told the engine can get as hot as 240* before damage starts to occur, but I would shut it down before that.

 

I believe the transmission is supposed to run a little cooler than what the temp of the engine block is (around 175), so it would depend on whether you want to monitor the transmission temp or the coolant temp. Not sure I want to wait until the transmission temp gets up to 225 before it alerts me if that is what you are looking to do. Here is a good thread on the subject.

https://www.naxja.org/forum/showthread.php?t=1026517

 

Yeah I would rather just run a trans temp gauge. I think if it gets above 170 or so and I better dial it back a bit. I am hoping that my wife doesn't need to pay much attention to the trans temp, but who knows. I think if it doesn't show signs of getting hot climbing the foothills with AC on then I'll probably just run a gauge and skip the light. The engine temp could jump up quickly with little warning for any number of reasons and I'm more worried about that happening. Thanks for the link!

 

I'm interested in a write up about this. I think its a cool concept that any 20+ year old car, or any car for that matter, could benefit from.

 

I think in your Jeep you have a port for doing a trans temp gauge.
I have read about it here and there. But they changed them at some point
and pretty sure mine does not have that port.

When does the idiot light for the coolant temp come on in an '00 with just an idiot light gauge cluster?
This is kinda of backwards but guys are always swapping them out for a gauge cluster.
Probably pick up one cheap.
And being an '00 almost positive it is plug and play.
The only concern is the mileage reading on it.

 

Correct. I'll add one eventually. A light or sound for when the Jeep gets to 225 would be great for when you let your guard down and aren't staring at the temp gauge.

 

You have never owned a Fiat....

 

Mine did not come on until my engine temp gauge pegged out at 260. There is a "Check Gauges" light that comes on. My thermostat stuck and so it jumped really fast on that occasion.

 

It's a good read except for the person who insists (incorrectly) that the factory heat exchanger inside the radiator doesn't cool the trans fluid, only heats it. He's assuming the coolant inside the radiator is 200-210*F and therefore can't cool the trans fluid. However, the coolant loses heat as it flows through the radiator, so by the time it gets to the cool side of the radiator where the trans cooler is located, it's dropped considerably and can pick up heat from the trans fluid (assuming the trans fluid is hot enough to need cooling). This is why it's recommend to leave the factory heat exchanger in place when installing an auxiliary trans cooler.

 

I am talking about a cluster with idiot lights and not a gauge cluster. though.
Now you have me wondering if there is even a "Check Gauges" light on an idiot light cluster.
Bet there is but seems a little redundant. LOL.