User 52121

So it seems like my dash gauge is messed up - what I see under "Coolant Temp" under the Rogue Logger doesn't seem to match what I see on the dash gauge. According to the logger I'm averaging 198-200F at cruise on a 85-degree humid day yesterday. But my temp gauge is all over the place. I've also noticed that the fan kicks on at ~215 according to the logger but the temp gauge is just about in the red before it comes on. (It used to come on right as it would hit the top white line before I cleaned the contacts).

I'm inclined to trust what I see in the DME since the fan behavior seems correct as well but figured I'd double check.

Long version of the story:

It started when I decided it'd be a good idea to clean the "footballs" and contact strips on the back of the cluster. I've had an issue for the duration I've owned the car where the voltage gauge on the dash reads low. Over the winter (JUST got car running last weekend) I did a complete "Robby" battery harness and also installed a low mileage underhood DME harness and kinda expected all that to fix the voltage issue in the dash - but it didn't. Reading here on RL I found some discussions about cleaning the "footballs" so I decided to give that a shot. While I had the cluster out I decided to clean ALL the footballs.

That's where things seem to have gone wrong.

Any sort of bump in the road would cause the temp and voltage gauges to bounce wildly after I cleaned the footballs and contact strips and put it back together. My concern spiked when I noticed that the temp gauge liked to read hot when rolling down a smooth road. I also did a fresh motor over the winter so I'm monitoring temps (still bleeding the cooling system) and seeing these high temps on the gauge is freaking me out. I keep staring at the logger as I drive and it seems the logger is makes sense - it's the dash gauge that's messed up. I'd like to fix this as I can't drive with the logger all the time

I tested the temp gauge using Clark's Garage procedure and the gauge is accurate when the car is sitting still in the garage. I ran a fresh, new wire direct from the sending unit in the head to pin 12 at the cluster and the behavior didn't change. I swapped in a known good sending unit and THAT didn't change anything either. I ran a ground wire from the football mounting nut to the ground under the dash and that didn't change anything. So I figured maybe I damaged the gauge when I pulled the footballs and picked up another cluster from a friend of mine who had one kicking around. With the "new" cluster the gauge is much more steady but still reads hot. (It still moves up and down a lot, like it's typically done in the past when I needed to bleed the cooling system, but it's not erratic and wild.) What are the chances I got TWO messed up gauges? (For the record the voltage gauge in the "new" cluster was definitely messed up - it pegged 15v on the gauge - which was definitely NOT correct...)

gruhsy

My gauge is doing the exact same thing. I took my car out for the first time the other night since last fall. Within 5 min it spiked into the red. I smacked the cluster and it fell back to barely registering and my oil temp gauge was so low it was not registering.

I am going to tackle the thing at some point....

If I find anything that works I will let you know. Everything on my car is new except the gauge cluster of course

User 52121

Thanks. I am tempted to try finding another gauge but don't want to throw away $$$ either.

I'm going to figure out a way to wire up my ohmmeter to the actual sending unit just to verify the signal coming out of it makes sense.

Dougs951S

Im always inclined to trust datalogs over gauges when the sender is known to be good. My temp gauge is jumpy sometimes and sometimes spike into the red when sitting, but datalogs show the temps never get over 185 so ive learned to ignore my temp gauge when it acts up. Same story with the oil pressure, It shows 3 bar at startup amd quickly falls to 0 pressure but a mechanical gauge confirmed I have 5 bar at startup and 3 bar at a hot idle.

User 52121

Well something is definitely screwy. I thought I noticed something on my way into the office yesterday and was able to repro it 100% of the time on the way home. I wouldn't believe it if I didn't see it myself.

Basically - temp gauge reads high. Voltage gauge bounces all over the place. If I squeeze down on the brakes, such that it's fairly aggressive braking (with some g-forces), both the temp and volt gauges drop to their normal levels. The harder I brake, the more quickly the needles move to their normal positions and stop twitching. As I ease up on the brake, the needles return to reading high/twitching. If I brake hard all the way to a stop, the gauges read normal right up until I stop... then they boink back up into their previous high/wrong positions.

It's not the brake switch - it's 100% related to the intensity of the braking. The coolant gauge acts more like a G-meter.

Bizarre. The harness in the car is stiff and can't really swing/move around so I have NO idea WTF is going on but it seems like it's something that swings forward under braking then returns to normal. I'll have to climb around under the dash I guess to see if I have any wires dangling.

*sigh* Cars suck.

On top of all that I discovered my turbo coolant pump isn't working. Turns out the solenoid took a dump. Luckily Lart came to the rescue.

User 52121

Fixed it. Did a combination of cleaning the under-dash grounds (did them a year ago, they were still shiny), re-routed a couple extra wires I had running under the dash (for my V1, boost gauge light, and LC-1), and re-tightened down the battery cables... and the problem went away.

Also added separate Water and Oil Temp gauges below the radio, as a fail-safe.