Electronic Climate Control counts down from 30 instead of running (93 Fleetwood)

Started by dochawk, October 03, 2022, 12:48:36 PM

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dochawk

I'm starting a separate thread here, as this seems completely unrelated to the now solved fan problems, and mixing the two would probably induce confusion among those searching for problems.

When I turn on electric, even before ignition, the Electronic Climate Control display reads "30" and counts down, roughly every second, down to "1", and then repeats. It continues this behavior after starting.

"Auto" is lit to the right of the number, and nothing else is lit.  No minus, and no segment test on startup.

Yesterday, the AC simply didn't engage, even with the temp turned all the way down.  The compressor sat there unclutched on the serpentine belt, and the secondary fan didn't come on.

Because it's both, I presume that something wasn't telling it to come on.  The controls still worked yesterday, though.

I disconnected the battery for several minutes, and the behavior is the same.

I checked all three passenger compartment fuses labeled HVAC in the owner's manual, and two more under the hood.
I've tried holding down off and warmer, but no response.  For that matter, no response to any of the buttons.

The previous owner installed an aftermarket stereo, so I can't go there for diagnostics (if that's how it works on this one).  I have the factory stereo in the trunk, but haven't been able to get the aftermarket out.  It appears from the FSM, though, that diagnostics (at least for climate) are supposed to appear on the ECC (p. 1C-7)

I haven't deliberately disconnected anything in the recent work other than the fan relays, the battery, and this:

IMG_0882.jpg
(which I reattached; I needed it to get the thermostat housing cover off).

I'm baffled. The closest thing I can find with any vague similarity on an internet search is is a list of codes that can come up on a Bonneville, and the diagnostic mode for the ECC.
1972 Eldorado convertible,  1997 Eldorado ETC (now awaiting parts swap from '95 donor), 1993 Fleetwood but no 1926 (yet)

TJ Hopland

That sensor is most likely the coolant temp sensor used by the ECU.  There should be a similar looking sensor on the side of the head near #1 spark plug that is used for the dash light or gauge.  I have no idea if the climate control knows or cares about the coolant temp and if it does if it has its own sensor or gets a signal from the ECU.  Historically Cadillac climate controls did have a engine temp sensor but I don't know if that continued for this model or if this was the same climate control that you got in the Roadmaster that didn't have Cadillac features. 

80's diagnostics read out on the climate control.  90's read out on what I think they called the information center which among other things read out MPG.  I'm assuming that since this car is a combination of Chev truck and Roadmaster it doesn't have that?   
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

dochawk

The "Automatic Air Conditioning" section of the FSM says that it displays things ranging from ABS trouble codes to engine coolant temperature on the ECC display, initiated with simultaneous off and temp-up.  It will display categories in sequence counting up, or be prodded, with a "-" in front of the category (after its segment test).

Gosh, I wish I'd known that a few days ago; I had assumed the display was on the factory radio, as with the 89 (?) eldorado my daughter briefly had before slayinh it, and the '93 Eldorado Touring Coup that I had for her older sister before she slaughtered that little bitty furrin car with it. (I think it's in the instrument cluster on my '97 ETC, but it's been out of service a while).

Anyway, it doesn't get as far as doing that, or being able to engage the diagnostics.  This countdown, with no preliminaries, begins the moment ehe electrical system turns on and before ignition.

I've read the whole FSM section, and it doesn't hint at this as a possible behavior. 

1972 Eldorado convertible,  1997 Eldorado ETC (now awaiting parts swap from '95 donor), 1993 Fleetwood but no 1926 (yet)

TJ Hopland

Does the manual have a troubleshooting chart based on codes?  How about the sequence of self tests?  Maybe scan through those and see if you see anything that mentions the countdown.  To me that sounds like its in one of the self test modes testing something and or waiting for some sort of response.   The self test you follow along with and it will have you do things like step on the gas and hit various switches along the way.
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

dochawk

Quote from: TJ Hopland on October 03, 2022, 01:47:19 PMDoes the manual have a troubleshooting chart based on codes? 

Sure does.  And it assumes that this thing is working and gives them to you!
::)


Quote from: TJ Hopland on October 03, 2022, 01:47:19 PMHow about the sequence of self tests?

Same thing.
 >:(

Quote from: TJ Hopland on October 03, 2022, 01:47:19 PMMaybe scan through those and see if you see anything that mentions the countdown. 

The word "countdown" doesn't appear in the FSM.

The first appearance of "count" on the same page as "downs" or "down" is hundreds of pages after this section.

QuoteTo me that sounds like its in one of the self test modes testing something and or waiting for some sort of response.

I've tried all the buttons on the ECC. I just went out and tried the various headlight controls, gas, and brake (sheepishly catching myself before I tried absentmindedly for the clutch! :o ).

I've ordered what may be the module, ACDelco GM Original Equipment 15-71971 Heating and Air Conditioning Blower Control Module, found with that wonderful delco site that Lauren posted a day or two ago.

I *think* I've found replacement instructions at 1C-58, but they keep calling it different things, so . . .

gosh, I just want to go home!

And it arrives Wednesday, and amazon has been coming late evening . . .
1972 Eldorado convertible,  1997 Eldorado ETC (now awaiting parts swap from '95 donor), 1993 Fleetwood but no 1926 (yet)

dochawk

to be clear, here is video of the ECC as I turn power on.  After about 5 seconds, I start the car, and it starts again.


http://dochawk.org/caddie/countdown.b.mpg)
1972 Eldorado convertible,  1997 Eldorado ETC (now awaiting parts swap from '95 donor), 1993 Fleetwood but no 1926 (yet)

dochawk

curiouser and curiouser . . .

I turned on the electric to pop the trunk as I packed for a planned 4am departure.

And the unit sat there like nothing ever happened. 

I turned over the engine, and it started blowing.

Uhm . . .

(and, actually, today with the monsoon rains would have been *great* for driving through the desert with no AC . . . but we did't know it was going to come down like *that* until it happened!)
1972 Eldorado convertible,  1997 Eldorado ETC (now awaiting parts swap from '95 donor), 1993 Fleetwood but no 1926 (yet)

klinebau

Strange intermittent problems related to electric components can often be attributed to bad or missing grounds.
1970 Cadillac Deville Convertible
Detroit, MI

dochawk


Update:

Yesterday evening, I used the electric to pop the trunk--and noticed that the ECC was just sitting there like it's *supposed* to with a temperature displayed.  So I started it, climate fans ran, and I  think the air was cold. Hmm.

So I waited for a decent hour to leave this morning.

And found that the windshield wipers wouldn't work.  But there wasn't supposed to be any on my path, so I went.

Climate fans still running, for the first hour or two.  then they started coming on and off every few seconds, and then stopped altogether.

But the ECC stayed live and functional, and I was able to use it to monitor coolant temperature.

It breathy much went back and forth between 89 and 92C the entire way (192F and 198F) [apparently, it only measures in increments 3C).

On a couple of serious grades (but not all of them) and in extended stop-and-go, it hit 95C, and dropped to 86C a couple of times on extended downgrades.

So at least cooling is working.


Quote from: klinebau on October 05, 2022, 12:08:47 PMStrange intermittent problems related to electric components can often be attributed to bad or missing grounds.

that could indeed explain a lot.  And I'vefoudn a couple of disconnected ground to deal with already.

But also, some seem to be symptoms in the FSM of a bad HVAC control module.  When my mind is less fuzzy come morning, I'll look at the wipers in the FSM.

1972 Eldorado convertible,  1997 Eldorado ETC (now awaiting parts swap from '95 donor), 1993 Fleetwood but no 1926 (yet)