Overhead Temp Display Reading “- - -“, (NOT the common 510 resistor Issue)

Hello TW,

I’ve been battling to get the overhead temp and direction display to work in my 2008 OR.

I recently bought a new OEM display to replace the old one, which was dead despite having a professional attempt to repair the classic burned out 510 resistor. Upon arrival, the new unit lit up, calibrated, and seems to function normally, but is not reading temp, just showing - - - F. I got a suspiciously good deal on it on Bonanza but it appears to be a legit, uninstalled OEM unit where the 510 resistor area is redesigned.

I’ve tried plugging in a new OEM thermistor and still get the same result. If the display and thermistor is good, I’m assuming there must be a wire connection open somewhere.

Can anyone advise on whether they’ve had this problem, or where/how to check the wiring in the car to identify if a signal is making it up to the display? I know a few threads exist related to this already on TW but none seemed to contain an actionable solution.

 

The thermistor and the ambient air temp sensor are different things.
What one did you replace?

This is the overhead (ambient) temp sensor.
You will have to zoom in to see it.

It is on the center support just below the hood latch.

 

it was my understanding the ambient air sensor was also a thermistor. Regardless, yes that is the one I tried swapping briefly with an OEM one. No difference.

 

You may need to check wire integrity.

 

where did you get this diagram from?
Would you check continuity with a multimeter at various spots, or just double check connectors?

 

First, I’d unplug the temp sensor and see if the display changes.
If the display changes, we probably have a sensor issue.

If not, then unplug the connector at the over head temp display. (Do this before the next step)
Then, Disconnect the temp sensor and jump the wires on the connector.
Go back in the truck and test the 2 wires (Yellow and Grey) for continuity.

You could do the same with a low amp test light.
But you’d need a long jumper wire. The above method should suffice in your case.

 

So I ended up testing the sensor and the wire - they're all good. I contacted the seller who sold me the part, they said:

"The part was brand new…it has to have the body control module reset to sync the system…you can not light it up and have it work without resetting this with techStream or similar software…it is not plug and play."

Does this sound normal for this type of part / is resetting the body control module a can of worms that would be not worth it for this novelty display?

 

Are you sure it's the correct one for your year model?
There was a couple different ones depending on year and they aren't interchangeable.

There is no reset/pairing for those, they are plug and play providing the wiring and sensor is there.

 

That's what I thought too. The listing from this seller says its 83290-04030, for 2005-2008 Tacoma, and I have a 2008 TRD OR. The price is suspiciously good when a lot of the other ones sell for $160, but this seller seemed legit so I took my chances. The part appears genuine and new and still has cling film on the screen.



The only thing that sketches me out is that it is 83290 - XXXXXX, rather than clearly stating that it is 04030. Also, while I assumed they had re-designed the faulty 510 resistor area on this board, it does look quite a bit different:

 

Yea that's odd that it would have a different sticker, I'm always nervous about stuff on Amazon and ebay that's way cheaper but claims to be the real thing.

What was wrong with your original meter?

 

I don't have one, but I'm just curious about the '510 resistor'. I had an old Subaru Forester that the LCD clock was not working. It was common for a 510 ohm surface mount resistor's connections to disconnect. I repaired it for a while by just resoldering the resistor in place. I've done tons of soldering for over 50 years but that's the only time I worked with a surface mount component, and I found it tricky.

On the old unit I do see what appears to be surface mount resistors like the one I resoldered.

 

That’s what happens.
The solder joint cracks. At first the the display will work off and on at random times.
But eventually it stops. It’s obvious when you open it up. You’ll see the crack in the joint, and the resistor will be poking up slightly on that side.

I think it’s bad solder. Or the type they used.
I had a CB shop repair mine. Charged me $5. Gave him $10.

 

Classic 510 resistor. Fixed it myself once, on second attempt to fix I must have screwed of up because Even after a pro resoldered the resistors it won’t Light up. Been chasing trying to get the frigging thing to work ever since. It’s really not even something that useful but it not working and being visible every time I start the car bothers me more than it should..but it’s hard to justify $170 for a new display.

 

Kinda like when I brought my radiator from my '67 Chevy to a repair shop in 1976. The guy welded it for $1, I gave him $2.

Surface mount is tough to work with. 510 ohms must be a common value with LCD displays.

 

Did you ever get this issue resolved? I'm having the same issue myself. Verified that the roof module is functioning and the solders are all good. Even replaced the sensor, but no luck.

 

Might be a poor connection on the sensor.