Author Topic: Blower motor - no HIGH speed  (Read 1237 times)

Offline Rcf

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Blower motor - no HIGH speed
« on: November 03, 2021, 12:19:29 PM »

The blower motor on my 1983 K30 did not work.  Apparently the truck came with AC, but it has been removed.  I replaced the blower motor, resistor and relay.  Now the blower motor works on LOW, MED 1 and MED 2.  In HIGH the blower reduces to a medium speed.

Before the parts were replaced, when I turned the motor on there would be no reaction in LOW, MED 1 or MED 2.  When the switch was placed in HIGH, there was an audible click from outside the cab presumably at the relay - just once each time the switch was placed in HIGH - but no other reaction.  At first I thought it could be the switch, but the audible click tells me the switch is at least sending a signal for something to happen.

Any ideas?  Would appreciate any input.   

Online bd

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Re: Blower motor - no HIGH speed
« Reply #1 on: November 03, 2021, 12:55:31 PM »
The 12-gauge red wire from the blower relay should route directly to the firewall junction block where it receives B+ power from the starter solenoid 3/8" battery cable stud via a different 12-gauge red wire protected by a (wait for it) fusible link.  We just discussed the issue of missing fusible links.  If you haven't already done so, you need to get the wiring properly fitted and protected as your first priority.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline Rcf

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Re: Blower motor - no HIGH speed
« Reply #2 on: November 03, 2021, 03:34:20 PM »


Fusible links certainly are a priority and will be put in place before the truck leaves the garage.  Thanks.

And I wanted to post that I found the problem.  As I was working on something else, the thought came to mind about the audible click I heard when the fan was turned to HIGH.  The sound had to come from somewhere, and the resistor couldn't do it.  So, I re-installed the old relay and HIGH worked.  I switched back to the new relay and lost HIGH.  So, basically, I bought a bad relay.

Thanks for your help and the reminder!!

Online bd

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Re: Blower motor - no HIGH speed
« Reply #3 on: November 03, 2021, 04:40:00 PM »
I'm happy to hear it was that simple and you found the solution straightaway.  I'm looking out for your best interest.  My concern with the fusible links is that you don't have a mishap in the meantime.  I've been involved with remedying several vehicle fires after-the-fact.  It's ugly!
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)