Use HVAC display as tach

[efnfast]

My 90 #1786 is in C.

[ghlkal]

Originally Posted by scottfab

What is the Serial number of your 90?

#2180

The display wasn't showing a temp in F, it appeared to be about 1/2 the temp gauge reading. So it could be in C ...

[aafc]

my 1990 #2546 temp shows c

John
1990 white/black auto eq.

[scottfab]

I checked mine on #16.
It is indeed in C.

I was reading my notes wrong in the manual.
I placed an arrow into the table which is missing #16 and wrote
"16 is the water temp not in F". So much for my hand writing.
I missed the "not" when reading it.

Sorry for the confusion.

[scottfab]

Originally Posted by Dynomite

I am now wondering what other interesting diagnostics are available similar to the HVAC diagnostics?

There is a lot of diag stuff (on a 90 MY) via the ECM and displayed on the dash, both active and passive. As I remember this is not available on other MYs. I should say there is some there but not as much as on the 90.

[VetteMed]

Originally Posted by Dynomite

2. Since the parameter #16 digital readout is in deg C where deg F=((9/5)(deg C) +32) and the gauge is analogue can we assume the temperature data for the HVAC digital temperature reading is from the same sensor and exact (in other words like the tachometer we can calibrate the temperature gauge)?

The temp display is taken directly from the ECM, which gets its information not from the gauge sensor, but from the other sensor right next to it.

[VetteMed]

Cliff, that's correct!

[Livin' in the 80's]

Originally Posted by VetteMed

The temp display is taken directly from the ECM, which gets its information not from the gauge sensor, but from the other sensor right next to it.

Do you know the locations of these two sensors are located?

[Paul Workman]

Originally Posted by Livin' in the 80's

Do you know the locations of these two sensors are located?

Yes. They're both located on the drivers side IH, toward the front. The plenum has to be removed to access them.

[Gunny]

doesn't seem to work on mine