Jump to content
CaddyInfo Cadillac Forum

Any Ideas what caused the HVAC head to go wacko 1993 sedanDeville 60 special ?

Recommended Posts


Car has not been driven for like 1 week, due to the 100 plus daily weather for weeks I cold started the engine and while parked for 5 minutes

I than pressed the auto button of HVAC control head. A/C was on but few minutes later the screen of the head showed HVAC wacko in that would cycle

everything heat, A/C, fans, defrost, etc Just keeps doing that and even pressing the off button within a minute comes back on and cycles again

Even turn the car off for like 5 minutes and starting it again on its own the HVAC keeps cycling, I can tell A/C coming on and off, changes of fans speeds, etc

Using OBD1 scanner, find no error codes tripped

Any ideas on how to debug/fix this ?

Thanks for any ideas !

Link to comment
Share on other sites

I don't have the same car but had something kind of similar.

I have a 95 Fleetwood Brougham.  When I looked at it (a couple times) and drove it all was fine.

The day I bought it, I was driving home and noticed the HVAC head was dark! 

I pulled it out of the dash and opened it up and it actually had a blown capacitor on the board.  Split wide open.

I suspect you may have a physical problem.  Might be worth a look.

I bought a used one off EBAY and put the faceplate from my unit on the EBAY chassis.  Mine was cleaner.  Been working for 12 years now.  Knock on wood...

Link to comment
Share on other sites

Prob. your climate control has failed. 

Check for 16v? from the BCM to the controller. 

Orange and black wire IIRC.

If you have this then the climate control unit has failed.

Best to hit up your local pic-a-part yard and get a spare.

I have had 3 controllers fail on my 93.

93 DeVille-13 Chevy Impala

72 GTO - 77 Triumph Bonneville

84 Z-28

Syracuse NY

Link to comment
Share on other sites

Thanks for the replies guys

Last night I turned ign key on but engine off and the climate control was off as normal

I then started and let engine idle for about 5 minutes and still ECC still stayed off and not doing what it was doing early in the day

I did not dare turn A/C on in fear of the ECC going nuts again

Wondering if for some reason the ECC could not talk to the BCM, so it was going nuts

Here in Texas the weather has been over 100 deg with heat index around 120 deg for like 3 months now and caddy is outside so wondering if some part in ECC or BCM got wacked ?

Very odd as when it went wacko even while driving the A/C was coming on and off, fan speeds changing, turning defrost on/off and would never stop doing this


What is required to take apart what is needed to get to the ECC and take it out and any tips on getting this out with ease ?

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Create New...