Hi Everyone, haven't been to this board in a while since I sold my other 4runner. But, I missed it so much I bought another one, an 87 4runner with the 22re. Since then, the dash temp gauge has been both inaccurate and crazy, wildly jumping from cold to hot to normal and back for months. After searching everywhere for a solution, I finally decided to get out my oscilloscope and find the real problem.

So, here it is for anyone that is interested:

If your 22re temp gauge is acting funky or is plain wrong, here are the steps to fix it. First, check the temp sender on the intake manifold between the intake runners, next to the block. Be sure that it reads a resistance to ground between 56 ohms and 500. The resistance will change dependent on the ambient temp and the engine temp. If that is working, check the actual connector on top of the sender to make sure that its not corroded. Replace if necessary. Next, if the gauge still does not work, you are going to have to remove the cluster. No big deal, really, it just takes a bit of doing. You will need a drill with a phillips bit on an extension and start removing the screws the hold the upper and lower dash together. When those panels are taken off, reach your hand (or find someone with a small hand) to reach behind the sub dash behind the cluster and unplug the speedo cable. Hint: there is only one clip and its on the top. Push it down toward the floor and the cable should come off easily. Next, unplug the plugs on the cluster and take it out. Then, take the cluster and gently set it down upside down on your workbench on a towel (so you don't break the mileage reset button) and look at the printed flexible circuit board on the rear of the cluster.

The screws on the cluster were not mounted from the factory using any type of locktite or anything to hold them in place. If your truck was in a hot climate (like 115 degree summers in modesto, CA) most likely the screws have loosened due to thermal cycling, making intermittent contact with the flexible PCB. When there is intermittent contact with the ground trace on the gauge, the device "searches" for a ground through any other connection-- this just happens to be the sender wire, going through the sender and making contact with the block at a substantially higher resistance than if the gauge grounded itself through the ground trace on the PCB. This is evidenced by toyota owners who have to punch the dashboard to make the temp gauge work, or when you notice the temp gauge jump to normal temp when the engine has been running less than 2 minutes.

To fix the problem, simply loosen the screws, spray contact cleaner on the flexible PCB and then tighten the screws again. Most likely, you will notice that the screws were barely attached when you removed them, owing to the fact that they loosened over time and there was no way to tighten them without removing the cluster. If you are bored, go ahead and tighten the rest of the screws on the cluster and watch all the other gauges function like new. There is the possibility that the entire cluster ground for the dash has also corroded. That is located on the driver inner fender underneath the kick panel garnish piece. Ground wires in 80's toyotas are white/black stripe-- so they should be easy to find. If this ground is loose or corroded, simply repair and retighten it and you should be all good.

Good luck and glad to be back!

 

That actually makes sense, I just finished moving the switches for the rear window to the radio area and when i went to remove the ground wire for the gauges the bolt head snapped off. I didn`t see any corrosion on the bolt or the grounds, but that doesn`t mean it wasn`t there. I ended up moving the ground wires to another threaded hole just below were they were originally mounted

 

Just registered on the forum. Don't even know how to use it yet. Trying to find solution to 86 toyota 22re temp dash gage not working. Did the Haynes repair manual suggestion of taking a wire and shorting it to ground, turning the ignition on and if the dash gage goes to hot, replace the sensor. Did that and sure enough, the dash gage went immediately to hot....so, I got a new sensor from Advanced auto parts, installed it, warmed up the motor, and nothing............very disappointed. Then the ''book'' says go to research the electrical.............I hate to pull the dash out to only find I still can't get it to work. Any suggestions?

 

By the way, if you have good suggestions on my dash temp gage I described above, you can EMAIL me, I may not be able to find your comments on the forum. I've tried to navigate it a little to see if others had comments, but had a had time finding the right subject. rhouse1938@comcast.net....................... ..thanks for your help.

 

thank you for sharing!

 

Hey, good thread. It worked! Took ten minutes.

 

I've been ignoring the temp gauge for months now . . . time to fix it I guess

 

Mine has done that a few times and I didn't really know why until now. I just got a combo gauge and mounted it under the radio. I noticed the factory gauge springs to life long before the mechanical one moves.

Good info though, I'll plan to tear into my cluster and ground wires soon!

 

My 87 runner temp gauge goes to half way as soon as the key is turned on. It stays that way no matter what kind of driving I'm doing. I replaced the sensor with no effect. Do you think it is a similar problem with the PCB ground?

 

yep, mine did that until I tightened the screws for the gauge. Give it a try.

 

I need to test the sender and then I will try this when I get time. I had a 4 runner that overheated and blew the head gasket so I want to know the temp at all times. Let you know what happens.

 

It worked!!! Thanks for that great post.

 

I fixed mine a while back and couldn't find the thread to repost. I removed the cluster and tightened all my screws on the back and that took care of it. It actually wasn't as hard of a fix as you might think. Good luck.

 

Bringing back an old thread! Hey I'm new to the forums and had a question. My temp gauge acts crazy. I turn the ignition on and it goes up to normal operating temp. When driving it will jump around, go to accurate, then drop all the way down and so on. I have done the following; new gauge temp sensor, thermostat, took out and retitened the scres on the back of the cluster( didn't have any contact cleaner) but the screws looked like new. And took off the ground under the panel by the clutch next to the door and sanded the connecter and part where you screw it in and still gauge is acting crazy! Also after I put the new temp sensor in( I did this last out of everything eles I did) i turned the truck on and unplugged the connector that goes onto the sensor and the gauge was still half way up. I don't know what eles to do. Any suggestions please and thank you I appreciate it I would really love to have my gauge working. 87 4runner 4x4 sr5 m/t. Thank you!

 

Is their another ground for the gauge cluster other than the one under the panel next to the door. Only 2 little wires? White with black stripe.

 

https://www.yotatech.com/forums/f116...luster-259564/
https://www.yotatech.com/forums/f116...curate-265837/

Take a voltage reading between screw A and B (+/-), if it's not steady voltage you've found the problem. There is a solution the first thread, and we're working on another in the second.

My new regulators should be here tomarrow. But it'll probably be a few days before it warms up enough to pull my dash apart.

I should point out I don't actually have the problem, but after I get a look at the insides I should be able to disable the internal mechanical regulator.

Wuffa has the problem but hasn't posted pictures or reported back yet.

 

Did you test the gauge following the FSM directions? Does the fuel gauge fluctuate also? If the fuel is steady you probably don't have the voltage problem.

 

Read the voltage with the cluster unplugged? And yes my fuel gauge is fluctuating. I just got the truck and filled up and after 65 miles it was at a quarter tank! I let it sit and went back out and now at a 3 quarters.

 

Is the gauge sensor the second sensor back inbetween the intake mani and the head right behind the thermostat housing?

 

Also I don't have a FSM if anyone has a link I would appreciate it (: