Hi all,
First time to post here. Mistsu montero sport 155k miles. Recently my temperature gauge has been reading max HOT as soon as i turn on the car. I know it can't be over heating seconds after sitting all night. i changed both sensors that read the coolant temperature to no effect, no blown head gasket signs, the car runs and drives great. As wired as it may sound IMHO something is wrong with the gauge is my conclusion i replaced the cluster with a known good cluster from another car and the temp gauge started working fine. I returned the cluster back to the family memeber that has the same car after my verification exercise.

Have you all heard of the heat gauge going bad while all other gauges are fine.

If so what is the cure? Feel free to get as technical as you want, i am a pretty technical guy myself.

I have repaired bad clusters before on a lexus LS400 and on a BMW. I desoldered surface mount capacitors on one and soldered the good ones on and the problem was fixed. Am i looking at the same thing here (desoldering bad components and soldering known good electronic componets)? i do not want to take it to the dealer becuase i know it will be upwards of $500 will be my only option if i go there, that is after replacing the sensor i already replcaed and tagging diagnosis fees.

If anyone has been through this, please point me in the right direction and i will take it from there. hopefully the suggestions will not be "replace the cluster" or "send it to XYZ to repair it for you" and if so then be it i just do not like being alone in this.

Thanks in advance

 

Im not familiar with your instrument cluster, but if there is a flex circuit, check to make sure all the traces are in tact and not broken. This is a frequent failure point as well. Find out how the temp guage works. If higher resistance = high temp reading, Id look for open trace or broken component... Good luck. With patience, youll find the problem. Please post what you find.

 

Yes, the back side on the cluster panel is covered with the flex circuit and then there is the printed circiut board in a corner about 2" by 4". I wanted to get as much info as i did before i start the cumbersome troubleshooting process.

I will keep checking this post on a regular basis just incase someone provids more input and will definetly add to the knowledge database if i find the problem.

Thanks tj90

 

I have a 2002 montero that is doing the same thing. It may go straight to hot just after starting, or go back to normal at any time. I have changed one of the sensors. That made no difference. I have used a lazer temp gague to check the heat and it is not getting hot. This has gone on for about a year. I posted here about a year ago and every one said to change the thermostat. I have been driving it this way since. Will be interested in what you find.

 

The V75W models have had issues with the circuit panel located behind the cluster, causing the temp gauge to malfuntion, the p/n is
MR532787. This part also stores the odometer reading if you replace it without recalibration your odometer will read 0.

 

2002 Montero (not Sport) Temperature Gauge reads normal when cold. It even reads normal when the sensor is unplugged! The needle moves freely and drops down to cold when the ignition is turned off.

Initially it read hot while driving from Canada to TN and I took it to a dealer. They replaced the temp sensor. No good. Flushed radiator. Replaced thermostat. Crimped off the back seat heater coils because they said crud was coming out. Problem not fixed but reassured engine temp was OK. Big bill! They recommended replacing the instrument/gauge.

Bought it home to local dealer. Replaced instrument. Another big bill. Now neither the Fuel gauge nor temp gauge worked. They told me the flexible printed circuit board needs replacing.

Finally I found the time to take out the instrument cluster myself. Cruddy soldering job! Multimeter testing showed that 3 solder joints to the instrument sockets were not making contact. I bypassed the damaged printed circuits by soldering thin insulated wires to bypass damaged connections taking wires directly from each instrument socket to the correct copper trace on the circuit board. Connections tested by carefully scraping the blue insulation off certain copper traces and checking conduction through the connections (continuity testing with Ohm meter).

Now the fuel gauge works but the temperature gauge reads normal even when the sender unit / sensor is unplugged. The needle moves freely and drops down to cold when the ignition is turned off.

MRP for a new instrument cluster is $860. $691 online dealer. Still too pricey. If no other solution I will install an after-market temp gauge and try to find somewhere suitable to mount the ugly thing and wire its light into the instrument cluster.

Any discussion at all would be appreciated.
Thanks.

 

After installing jumper wires from the printed circuit board (PCB) to the temperature gauge it still malfunctioned. So I talked to the Mitsubishi garage tech who had worked on it and he gave me an old instrument cluster housing complete with the printed circuit. Actually it is not a "board" but flexible blue plastic sheet containing printed circuits.

It was really quite easy to take all the instruments off my old cluster and install them in the new housing. Nice design.

After completion I thought it was fixed but now it is doing the same thing that it did originally. The temperature gauge slowly wanders up and down between normal and high over a period of a minute or less. Up and down and up and down it goes.

I unplugged the sensor or sender unit - a single wire on the aluminum pipe at the top front center of the engine. Then it stays on cold. Although the sender unit has been replaced by the first Mitsubishi garage (?) I think that may be where the problem is. So I will probably replace that next. I have a spare original temperature gauge and will check whether it does the same thing. I expect it will.

 

This problem persists even after switching to another temperature gauge. Tech says it is a bad connection, but it does this even if the car is sitting still without the engine running. Ordered a sensor. Lousy Mitsubishi parts service takes up to 10 days. Should have ordered online.

 

I have the exact same problem with a 2001 Montero Ltd. I had the transmission replaced, and after getting it back I noticed the overheating issue. The gauge immediately jump to the top, and I verified the vehicle was not overheating. It was scary to drive in this fashion, but I was convinced the problem was electrical, and that nothing mechanical was causing anything to overheat.

I returned to the AAMCO dealer and demanded that he fix whatever damage he caused. Of course, he denied any wrongdoing, checked his computer, and suggested that I replace a sensor. However, the computer identified more than one is a possibility. He stated they had nothing to do with his repair, and I was not in a position to prove otherwise. I paid for the replacement of the sensor, drove away, and within a block the temperature gauge was back up at the very top showing overheating. I immediately returned, whereupon he suggested the other sensor identified earlier may be the one causing the problem. I told him I wanted him to replace it for free since he sold me a sensor that had nothing to do with the problem. He refused any credit, and defended his action by saying his computer told him the replaced sensor was bad. Total horse crap. Again, I was in no position to prove anything. He wanted to keep on charging me for every harebrained idea that occurred to them. I told him to shove it. I elected to continue driving the car, which I have done without issue for over a year.

The problem I have today concerns passing an admissions test in Arizona. The car passed the test, but they flunked me anyway because the "check engine" light remains on. They agreed it otherwise passed. They also checked "catalytic converter," according to my wife, who has the car in another city.

I told her to take the car to an AutoZone and have it checked out for free. She did, and reported back that they checked off three possible problems, the catalytic converter, and two other sensors.

I reviewed all for him responses on this subject, and reviewed other posts online, and it appears there is really no fixing the temperature gauge issue, apart from buying a new car. Has anyone successfully made the repair? The posts here were made earlier, and I am just wondering if there is a happy ending? I do not wish to spend a lot of money down the toilet. Any ideas on the repair of the catalytic converter? All responses greatly appreciated.

 

Sorry for the typographical errors. I dictated the entry using Dragon NaturallySpeaking.