Author Topic: Blower motor not working- 83 1/2 TON 305  (Read 911 times)

Offline THE-JOSHTER

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Blower motor not working- 83 1/2 TON 305
« on: January 28, 2023, 03:38:42 AM »
Hey yall
So about 3 days ago my blower motor stopped working. Really a problem considering -20c temps are picking back up. Anyways pretty sure ive mucked up and just not fixed the problem which is where we're at now.
About three months ago when winter was just picking up my original heater was kinda keeping up kinda keeping the cab luke warm ish so i was looking into a possible new blower motor and i came across a forum post on blower motor upgrade. https://www.gmsquarebody.com/threads/upgrading-your-blower-motor.20764/ This one to be exact. did everything and as pretty easy. soon i I flicker her on it was pretty night and day from the old one. First thing noticeable tho was it would never run unless the switch was on high so i figured it was the resistor which was pretty old and rusty. Went out bought one but seeing as she was running atm didnt every swap the new one in. 2ND thing was that when every i flicked her on and i was either accelerating or had my lights on my battery light would be dim-medium brightness as if i was pulling a little extra than being supplied. Again im badly in the habit of not taking things seriously until theres a huge problem so never looked into it. Fast forward again to few days ago motor goes out an now when i flick the fan on the battery light glows bright as day. I swapped the new resistor in this morning no change. Checked the fuse no issue. Pulled in from work tonight and pulled the orange off of the motor and tested that to batt terminal and i got 16v going to the motor when switch is on high. Short term solution is im gonna get a new one tomorrow and swap her in so i have heat and can see the road but somethings not right

Should i have 16v going to motor? Sticker on motor say 12v motor? Whats the deal with my light? Motor burn out because of voltage??

never had these problems with the og blower motor for note. Im gonna get a new one in anyways just for short term but dont wanna do this every two months.  Also should note i dont have a/c options with truck

Appreciate the help as always thanks fellows

Offline VileZambonie

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Re: Blower motor not working- 83 1/2 TON 305
« Reply #1 on: January 28, 2023, 08:00:24 AM »
It sounds like you have a charging system issue going on. Swapping in a later model blower as an "upgrade" is another internet legend that is basically a waste of time. The quality replacement units are upgraded already. You would be better off upgrading your alternator. Search the forum for alternator upgrades based on what your needs are.
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Offline THE-JOSHTER

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Re: Blower motor not working- 83 1/2 TON 305
« Reply #2 on: January 28, 2023, 03:58:49 PM »
Hey vile thanks for the info. Electrical is not my forte so definitely anything sounds like a good idea to me . I can test everything but I dont know what to do with the info

I swapped in the new motor this morning still nothing. Got power going to but no luck. I pulled the connecter going to the fan switch and I have 16-18 volts coming from brown. I tested (I think) continuity between orange blue and yellow and all seems good. I had a 25 amp fuse in my pocket so I shoved that in the connector and linked up brown and orange yellow I believe and nothing returned it turned on the battery light just the same and moving the switch.

Again dont know bout electrical that much but ground would be the next thing to look for right? Im assuming the motor grounds to the firewall? Any ways I should test otherwise? Thanks again


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Offline JohnnyPopper

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Re: Blower motor not working- 83 1/2 TON 305
« Reply #3 on: January 28, 2023, 04:59:54 PM »
VZ pointed out that your charging system is suspect.

14.?v is what your alternator is supposed to put out.

Start there.

You may have burned out the motor... :(
1957 Apache 3100 235 Inline 6, 3 on the tree
1973 C-20, 3+3 454 4BBL TH400  Water Injection
1978 K-10, 350 4BBL TH350 NP203 M.M. Part time Kit/Hubs
1980 C-10 under construction