91 dynasty blower motor

Hi, I've got a 91 Dynasty, and I thought the blower motor blew about a week ago. I got another one and installed it, but no blower. I then (stupid) tested both motors, and found that BOTH of them work, but I can't find the
problem. I seem to have occasional random electrical problems, too (blue high beam light doesn't go on sometimes; radio display doesn't work sometimes, etc.) Anyone have any idea what could be going on? I just spent hours taking out the old motor and replacing it, so I'm a bit frustrated. :( Thanks!
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I just cruised through some archives, and think my problem might be either the blower motor relay or the resistor block. (Thanks HeadlessHorseman for your excellent link!) Can anyone tell me a bit about these two things? Specifically, I suspect the relay is bad. Any tips on where it is and how to replace/test it? Thanks a million; this is a fantastic resource!
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If your blower does NOT blow in the HIGH position and, as you say, your blower motor is OK, chances are excellent that the relay is the source of your problem. This assumes that you checked the FUSE and that's OK too.
When the resistor block fails, it doesn't usually entirely fail... only one or all of the slower speeds fail. Still, you should locate and inspect the resistor block because after 15 years, it COULD have entirely failed.
Since the AC/Heater Blower circuit is a high-power circuit, a relay (not a switch) is used to handle the juice. Sometimes, this relay becomes so pitted and burned with normal use (normal after 15 years, for sure), it simply will not close with good contact to provide power to the motor.
Sometimes the relay will remain closed after the vehicle is turned off, leaving the blower running after the relay literally welds itself in the closed position.
In both cases, a new $13 relay will fix the problem. If your resistor block is rusty or just looks bad, you might replace it anyway... a replacement resistor block only costs around $15. Save yourself a future headache.
--
HeadlessHorseman

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Resistor block is usually on plenum on passenger side of firewall.
Just unplug remove block and replace. About a 3 minute job.
larry
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You did try replacing the fuse, right? On my 1990 Dynasty, every once in a while I have to replace the fuse for the blower motor. Cost is between four and five dollars, so the price is right.
I'm told there is something wrong with my electrical system for that fuse to need replacing so often. From looking online today it appears that your year and mine are affected by the following
NHTSA Recall History 1990-91: On cars without automatic temperature control, water leakage under windshield cowl may result in corrosion of heater blower resistor terminals.
The only other symptom I know of when that fuse goes out is that the air bag light on your dash will come on and not go off as you drive the car. Some parts stores no longer sell that particular fuse but many still do. On my 1990 model it's a red 50 amp PAL autolink female terminal made by Littelfuse. Package card is purple. I found it on Amazon and ordered some spares. If it's not your motor or relay this is a cheap way to maybe fix it. Good luck
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