1990 HVAC Control Flashing

[EDS_5_OH]

I have a couple questions for clarification.
Some background:
I just got my interior all together and my engine started. I have a mix of to different years going on. My cab is a 1990 Z71 which I did not touch the HVAC system at all. I removed all the interior and replaced it with my 1993 interior. I swapped everything, dash board, wire harness, radio, and so on (with the exception of the HVAC system from '93). After hooking up power and starting the truck, I noticed I'm having the same issue as you described. I have the controller from '93 trying to control the '90 HVAC system.

I don't recall what the controller from the '90 looked like, or its functions compared to the 93, but you said in your last post that by installing a '90 controller the problem was salved? Could you help me out and explain what the "RECIRC" button is.

I should also mention I have not finished installing any of the A/C components under the hood. Everything is out and open, not hooked up. Did you check any of that stuff as mentioned in this thread before changing the controller?

Thanks
Nate

The RECIRC or MAX button allows the user to close off outside cab air when running the AC or choose not to. On the older models, it happens automatically since there is no button to choose from.

If there is a problem with the AC, according to my manual and what I've read on-line, the AC display will flash. My understanding is that this only applies to the newer version of the display, not the older series.

In my case, both the temperature scale and the air direction displays flashed after a couple of minutes of running, not the AC. They all still worked and you could adjust temperature and air direction but the display flashed. Installing the old style display (no MAX or RECIRC button) fixed this issue. My AC is not charged and I will need to retrofit to R134 or Freeze 12 to do so.

 

[91chevyLB]

I had that same thing happen in my 91' added some freon and it fixed it...this may or may not be off topic, the buttons don't always respond on my controls, like sometimes ac won't click on, or the "high" blower position won't work so on and so forth, bad or old solder?,

 

[BENT MT DAVE]

Hey,
I know this is an old thread but I'm having the flashing Temperature Scale problem.
Have had the the other one flash before but it usually just cleared up on it's own.
OK back up, 94' Silverado ECSB, all original equipment.
Bent Mt Dave

 

[someotherguy]

Hey,
I know this is an old thread but I'm having the flashing Temperature Scale problem.
Have had the the other one flash before but it usually just cleared up on it's own.
OK back up, 94' Silverado ECSB, all original equipment.
Bent Mt Dave

The only couple times I've seen the temperature portion flashing is because the actuator had gone bad. I just grabbed one from a parts truck and swapped it, no biggie, working again. It's not a position that often goes bad so even a used one is a decent bet if you can get it cheap.

Richard