Fixing the 77-79 Achilles' heel AKA Blower Motor Relay once and for all!
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RWD 19xx-1984 DeVille and Fleetwood,
1985-1996 Fleetwood and Brougham Forum Discussion, Fixing the 77-79 Achilles' heel AKA Blower Motor Relay once and for all! in Past Cadillac Vehicle Discussion; We all know about the infamous blower relay failures of the 77-79 era Caddys. I've seen a couple of fixes ...
  1. #1
    lacville78 is offline Cadillac Owners Fanatic
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    Fixing the 77-79 Achilles' heel AKA Blower Motor Relay once and for all!

    We all know about the infamous blower relay failures of the 77-79 era Caddys. I've seen a couple of fixes mentioned, which include a divorce kit, or wiring in a manually controlled rheostat.

    I decided to give it a shot with a new method I devised. I got rid of the underdash mounting, due to risk of a fire, and moved the relay to under the hood. I also decided to go ahead and add two more, thus splitting the load to one relay by two-thirds. I also strapped the 3 relays to the accumulator, thereby cooling them. I also decided to go ahead and stick a new blower motor on just to be sure the resistance was low.

    So far, so good. I might go ahead and fab a metal strap just to make it look a bit better, but to me the prettiest relay set up is the one I never have to mess with.

    PS. Please ignore the tape over the climate control housing, it was just a cheap way to fix a couple cracks.



    carnut and talismandave like this.

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    larryinalabama is offline Cadillac Owners Connoisseur
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    Re: Fixing the 77-79 Achilles' heel AKA Blower Motor Relay once and for all!

    Ive never had a problem with any late 70s Ive owned. I did have a 74 Coupe that had a slow burning "fuse" for the ac that alaways went out, I actually kept spares in the glove box.

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    Bro-Ham's Avatar
    Bro-Ham is offline Cadillac Owners Connoisseur
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    Wait...what??? You can't take away the charm of the blower relay problem on the 1977-79 models...I am practically a major shareholder in a relay company at this point the way I drive my car and burn up the relays.

    Please detail this more so we can show our mechanics or do ourselves. Great work!

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    lacville78 is offline Cadillac Owners Fanatic
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    Re: Fixing the 77-79 Achilles' heel AKA Blower Motor Relay once and for all!

    Quote Originally Posted by Bro-Ham View Post
    Wait...what??? You can't take away the charm of the blower relay problem on the 1977-79 models...I am practically a major shareholder in a relay company at this point the way I drive my car and burn up the relays.

    Please detail this more so I can show to my mechanic. Great work!
    Ya, I think I went through 2 or 3 of them before I got tired of that funky burning plastic smell.

    Its funny, I kind of installed this set up without thinking too much about it, now that I am working on making you up a walk through, I realize it is a little bit involved. It is actually harder to explain it all than just doing it.

    Give me some time and I will write something up for you.
    77CDV likes this.

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