Summer is here, and I have friends over for the holiday weekend. We have been taking the 4Runner all over Germany, and it has performed flawlessly.

One primary concern, however, is the inoperative temp gauge... You know... The one that sometimes works when cold, but jumps up to just below the halfway point when warming up and stays there. I know several people were working on finding the cause (and fix) for this issue, just wondering if anyone found it yet.

The friends have a newborn baby, so I have to run the A/C. There are a LOT of 15-20% grades here, and I know it is getting a bit toasty underhood pulling some of the grades (especially since I put my 33's on for the summer). I would hate to blow the HG again because I can't tell that it's too hot.

So, who is the genious that figured it out?

The closest I've seen for a fix is over on the ih8mud.com Land Cruiser board. They determined what resistors need to be swapped to get the gauge to read more precisely.

The logic behind the OEM gauge is that if it reads TOO accurately, meaning you see the needle move with only a few degrees of temp change, would send owners running to Toyota complaining the gauge was either broken or the truck is overheating. So, they put in a resistor that keeps the needle steady at the half way point and it doesn't move up or down for a broader temperature swing.

I do not know if the same resistor swaps as used on the ih8mud.com board are possible for a truck/4runner, but it's a start.

Install a real gauge and quit worrying about the stock gauges!!!!

Not the poblem. Some of our gauges like to go straight to the middle... Even 10 seconds after starting the truck in the winter.

Mine overheated several times in the past, blew all the coolant out of the overflow... Gauge stayed in the same spot. It doesn't work.

my SR5 gauges I swapped in my 85 do the same thing, the needle stays in the middle no matter what.
I am going to try swapping the sender to match the year/model I got the gauges from.

Yes.









Sort of.


Mine did the exact same thing, right after I swapped an SR5 Cluster in. Did it for a year or more, no matter what random things I tried (upgrading the cluster ground, etc.

About 4 weeks ago, I had the dash apart to fix a couple minor rattles and loose bolts. I took the cluster out and undid everything I did to try to fix the problem. I then tightened every screw on the back of the cluster. When I plugged it back in, I wiggled every single wire going into it AFTER I plugged in the connector. Those connectors really don't hold the wires all that securely.


It hasn't screwed up since. Nice, even needle rise to middle, no jumping around at all.

I may never know what did the trick, but something did.

I used to experience a temperature needle that would climb to the middle as the truck warmed up, and then randomly would drop to no reading, and then jump back to the middle... back and forth, back and forth... at times it just wouldn't work at all... I had this happen on two different trucks... conveniently, it happened after I changed the coolant in both trucks... I finally spent a BUNCH of time burping and reburping the coolant system... apparently there was still some air in the system somewhere... My problems finally fixed themselves... I think that if you have even the slightest amount of air in the system, that the air might congregate around your temperature sensor, which causes it not to work sometimes... But your problem sounds a little different...

A better way to describe the problem:

25* outside... Start 4Runner, drive for 2 blocks. Temp gauge buried in the cold. Leave stop sign, start accellerating... Temp suddenly jumps to the middle, sometimes popping back and forth to the bottom at random for a couple minutes, then stuck in the middle for the duration of the trip. Sometimes the gauge jumps to the middle as soon as it is running, but will always end up there within 2 minutes (even if idling in the driveway).

It doesn't matter if it's 8* or 80*... Same thing.

Hrm.. on a cold day.. mine takes a LONG time to get up to half (i'd call it running temp), and when i say cold, i mean like -25 celcius cold. At about 20-25 C, it takes about 1 km to hit half way.
I really only notice 3 temps, cold, warming up, and warm.
The gauge may tell me it's in the middle, but if i crank the heat, it's decently warm. Now, if i go on the highway at 120km/h+, THEN turn the heat on, it'll burn my pants (or so it feels)... not the most accurate gauge ever, i agree.

I could be in Minnesota in winter, it would act the same.

One other thing... Every now and then (rare) it will actually move slowly on a hot day... The 2 minutes are long enough for it to come off the bottom about 1/4" in a slow, steady motion. Then, POP... It jumps to the middle.