HVAC blower motor has no high speed 1998 La Sabre

[roysbuick98]

New to forum, I have a 98 LeSabre that the blower fan quit running on high speed

 

[HotZ28]

Do you have the manual system, or auto climate control?

 

[imidazol97]

If poster has a manual system, the high speed uses a different circuit to provide higher amp to motor. It may have a 30 amp fuse and uses a relay in the relay center to switch to that direct circuit. The lower 3 speeds use a resistor to vary the power to the blower.

Im on my phone. If you respond you have manual system, I'll look for circuit diagram.

 

[imidazol97]

I'm working on the assumption if this were the automatic
fan speed control system with that electronic control, the poster would
have a complaint that speeds vary at times or do funny things like
going faster or slower than usual. I'm guessing it's a manual switch.
with the lever that clicks from stop to stop.

So For a manual switch system, here's an old article with picture of the relays
and of the heavy fuses above it--Maxi fuses, is that what they're called.
I think there's a diagram in the owner glovebox manual for the maxifuses
and what each is for.

What I suspect is your high speed blower relay or its fuse for direct power shown
right belower the relay on the diagram is bad--or a wire. Most likely a contact, but
I'm guessing.

Note that the system names are confusing: the high speed blower relay is a 5
contact relay in the relay center with certain color wires into it. The Blower speed
relay is there also and has 5 contacts, but its purpose is to be to provide power
to the resistor part of the circuit and it turns the power off when the key is off.
If it failed, you'd have no speeds. That relay is at the bottom of this diagram.

https://www.buickforums.com/forum/lesabre-24/manual-control-no-high-speed-blower-motor-6800/

 

[roysbuick98]

Thank you for your quick assistance with my problem.

 

[imidazol97]

Please report back what you find.
BTW, the covers on the relays come off easily if you want to try cleaning the contact inside
if that's where your problem lies. I had a relay on a 93 leSabre fail that turned on the compressor
and I cleaned the contact which was really badly burned. Then replaced it.

 

[roysbuick98]

Please report back what you find.
BTW, the covers on the relays come off easily if you want to try cleaning the contact inside
if that's where your problem lies. I had a relay on a 93 leSabre fail that turned on the compressor
and I cleaned the contact which was really badly burned. Then replaced it.

 

[roysbuick98]

I finally got around to looking into it and found 1 of the relay pin receivers with purple wire has melted plastic around it. I attempted to post a picture but couldn't figure out how to reduce the file. Thanks again for your help.

 

[roysbuick98]

imidazol97 when you said you replaced it did you mean you replaced the female part of the wiring harness. I wonder if there is a source for replacing and rewiring that relay receiver. If you have any ideas let me know​

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