1988 Brougham Climate Control Problem - Page 2
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RWD 19xx-1984 DeVille and Fleetwood,
1985-1996 Fleetwood and Brougham Forum Discussion, 1988 Brougham Climate Control Problem in Past Cadillac Vehicle Discussion; If you ground the blower motor, does the system then control the blower speed? If you ground it and low ...
  1. #16
    carnut is offline Cadillac Owners Master
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    Re: 1988 Brougham Climate Control Problem

    If you ground the blower motor, does the system then control the blower speed? If you ground it and low and hi positions change its speed, I would think you have a power module problem underhood. The rear wheel drive Cads used a different module in the dash than the Eldo's and Seville's. Same wiring plug, same functions but it wont attach to the air box. Have you replaced one of the blower motor flange screws with a nut and bolt and made sure no paint is between the bolt and blower motor. If grounding the blower motor turns it on then it has to be a poor ground wire connection to it, I would think.

  2. #17
    C-Leb is offline Cadillac Owners Member
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    Re: 1988 Brougham Climate Control Problem

    Quote Originally Posted by cadillac kevin View Post
    As long as it looks exactly the same as yours (the early 80s had a different button layout), it should work. I don't recall if ones from eldorados/ sevilles will work (fitment wise) though. But ones from say, 86-89 brougham will work for sure.
    Have you checked your blower resistor pack? They seem to be a common source of annoyment on older GM vehicles.
    I'll check my FSM when I get home and see if I can figure out anything else for you.

    Edit: just thought of something for your outside temp reading. Is your outside temp sensor still intact? Is it unplugged?
    It is located in the top center area behind the grille and bolts to the header panel right above the grille. IIRC, you get to it by removing the plastic piece between the header panel and radiator support.
    if im not mistaken the ac power module under the hood is the equivalent of a resistor pack in the brougham I did get one from another 88 in a junkyard but nothing changed...
    If there is some other component im unaware of plz let me know.

    My outside temp sensor is plugged in and works great it read -02 last night (Fahrenheit) cold night not to have any heat

    ----------

    Quote Originally Posted by carnut View Post
    If you ground the blower motor, does the system then control the blower speed? If you ground it and low and hi positions change its speed, I would think you have a power module problem underhood. The rear wheel drive Cads used a different module in the dash than the Eldo's and Seville's. Same wiring plug, same functions but it wont attach to the air box. Have you replaced one of the blower motor flange screws with a nut and bolt and made sure no paint is between the bolt and blower motor. If grounding the blower motor turns it on then it has to be a poor ground wire connection to it, I would think.
    I have not replaced one of the screws but i never have the motor cut out once working. As I said in previous posts its only when its very cold outside that it wont work. Even when warmer i can only get the fan to come on by turning the temp down to 60, after the fan kicks in then i turn it backup to 90.
    Ive read about a feature that prevents the motor from running until the car is warmed up, going to defrost bypasses this but not on my car....
    Anyone know more about how this circuit works? I thought I might have a problem there unless its all controlled via the ECC unit...



    Sorry my problem was similar to the original post ive hijacked it, i never had my ecc reading -45 outside temp. Mine has always read properly

  3. #18
    The Ape Man's Avatar
    The Ape Man is offline Cadillac Owners Connoisseur
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    Re: 1988 Brougham Climate Control Problem

    Maybe there's a block temperature switch to lock out heat function while the engine is cold. Dunno for sure on an 88. After 85 I did not really work on these lines.

    If you call for defrost or set to 60 and the blower runs but won't work on cold days look for a block temp switch for HVAC. Those beasties were a problem on all older Cadillacs.

  4. #19
    carnut is offline Cadillac Owners Master
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    Re: 1988 Brougham Climate Control Problem

    I just looked at www.rockautoparts.com cataloge. Its shows a 5 pin relay for the A/C fan. A $6.00 part. worth a shot! DELCO part numbers, D1746C or 19106975.

  5. #20
    C-Leb is offline Cadillac Owners Member
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    Re: 1988 Brougham Climate Control Problem

    33720000169_large.jpg

    I found this and im going to go through the steps today, hopefully its not to warm.
    Only thing that confuses me is they talk about 2 separate parts, the programmer and the control head...?
    I thought there was just one the ecc module in the dash...

  6. #21
    carnut is offline Cadillac Owners Master
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    Re: 1988 Brougham Climate Control Problem

    Programmer, behind glove box. Control head, center of dash to set the climate mode you want. Power module under hood next to the fan motor itselfthat changes the fan speeds. Just dont go to either extreme on the temp display. stay below 90 and above 60. Both max temps will raise the fan to max speed. You not only want the fan to work, but you also want it to modulate the temperature automatically based on interior temp.

  7. #22
    The Ape Man's Avatar
    The Ape Man is offline Cadillac Owners Connoisseur
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    Re: 1988 Brougham Climate Control Problem

    Great you have the service notes!

    I'd try reseating the connectors on the control head, programmer and power module. They may have a loose connection. Just a shot in the dark but a cheap one.

  8. #23
    coodeville is offline Cadillac Owners Member
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    Re: 1988 Brougham Climate Control Problem

    The price of a power module is now 235 bucks. A lot better than the 400 it was five years ago.

  9. #24
    cadillac_al is offline Cadillac Owners Connoisseur
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    Re: 1988 Brougham Climate Control Problem

    I wonder if the blower motor is just worn out and only comes on when it gets a full 12 volts, either by jumping it or setting the control head to 60.

    FWIW my old Seville had the blower control bypassed with a push button when I bought it. I assume somebody did this when they were cold and tired of troubleshooting. I have never fixed it in 18 years and still use the push button when I need some blower. This may be a good temporary fix to get you through the cold weather anyway.

  10. #25
    C-Leb is offline Cadillac Owners Member
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    Re: 1988 Brougham Climate Control Problem

    Blower motor replaced.
    Like I said before it only wont work when its -30 out, so very hard to troubleshoot and COLD!
    We had a couple cold snaps in the last few weeks and a few times it didn't work. Went through the troubleshooting tree and eliminated the module, the motor and wiring under the hood. Took the kick panel off and it started working.....
    Im inclined to agree with The ape man, I think one or more of the pins at my programmer is loose and when it gets mega cold they contract and don't maintain good contact. The next ffew times I started it and the motor wouldn't kick on if I wiggled that harness it would kick on everytime. So I went through all the pins on the connector bending them as such so they would stay in contact with the programmer better. Everything seems fine now! YAY!!! but we haven't had a bad cold snap since then....
    I REALLY REALLY REALLY hope this is finally fixed, ive had enough after 2 cold winters!!

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