#1  
Old 07-24-2022, 03:29 PM
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peppergreen peppergreen is offline
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Default Blower Fan Quits

Folks, been a while, back for that great advice!

67 GTO w/ A/C

Blower fan has been quitting last few days.
Dash fuse is good.
old relay, had the Lectric repro in trunk so I replaced.
resistor is new repro from a couple years ago, looks good shape
all connections are clean, dielectric grease on spades.
30 amp fuse at alternator is good, made sure connection is tight.

I have power on grey wire everytime, can get the relay to 'click'. The dash switch and grey activator wire are good.
Fan runs, but without warning when driving, I notice it isn't working.
Back to garage, pull relay, put jumper from hot blk/org wire to brown wire, fans starts to run everytime, so fan is good. Put relay back, tight, grounded, clicks, sometimes fan works, sometimes it doesn't. When it does, it does not like high setting. Within seconds, it is kicking out. Runs OK on other 3 settings, but without warning will quit. Wont start again unless i take relay off, play with it, always have the grey wire clicking.
As before, if it quits, it doesn't usually start again, unless I pull connector and jostle things, may take a couple installs, then it starts working again out of the blue.

Wonder if the old, original A/C wiring harness is shot. My question is I don't know what would be causing the blower to quit. The 30amp fuse at alternator? It's a fuse, so surprised it wouldn't just pop, not "reset" if there was fan overload.

My next trick will be to jumper the hot wire to brown wire with relay removed, and watch it for a bit, go through the speeds. I haven't done this, I hate jumpering, get the fan going for 15 seconds, then pull my jumper off, I will leave it longer to see what happens.

Maybe that will tell me if connection is bad, or something getting hot. I see there has been some slight melting from years ago on the connector to relay, wiring overall and other connections looks good, no hot spots.

Simple as a pooched relay? Figured if it clicked to allow power to go through it, it would be good, but who knows. Not sure what the inside looks like on repro compared to the original, I have put the orginal back on, can't get the fan to run with it, but the repro will get fan going, just kicks out in 30 seconds or less, right away if on high.

Definitely will order new harness and relay, but would be nice to get this glitch sourced, as insanity is starting to set in doing the same thing over and over with same results!!

Thanks in advance, lots of posts on relay issues, but couldn't find one that was similiar problem.

Brent

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  #2  
Old 07-24-2022, 06:22 PM
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With relay installed fan won't work. drove 5 minutes, fan quit. Removed relay, put the jumper on male connector side from blk/org hot wire to brown wire, fan turns on fine.
Runs on low for 3-4 mins fine, same as #2
Switch to 3, runs for 2 mins, starts to flutter a bit, down to 2, seems ok and still running.
On high, runs for 15 seconds, starts to wobble a lot, shutting off, was able to quickly get to Low setting, and it ran ok.

Re installed repro relay, fan is working again (???)

Next step is to try not to overload it, but I think I should get voltage readings before and after the resistor? Maybe that is causing some grief.

Weird, because that fan should get straight battery voltage when I put the jumper on the relay connector, nothing from the battery should get overloaded and try to shut down the fan---unless it's the resistor.

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  #3  
Old 07-26-2022, 11:11 AM
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sounds like bad fan motor, to much resistance getting hot and shutting down

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  #4  
Old 07-27-2022, 08:19 AM
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Try to get a current reading on the fan motor (DC amp meter), and a resistance reading on the motor. If it's the original motor ... very good chance it's going to be marginal.

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  #5  
Old 07-28-2022, 03:34 PM
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Thanks for the advice guys, appreciated.
--Update, lots of alligator clips and wires last couple nights! I decided to take time and start isolating each component to find the issue.
I unplugged fan motor and just ran the voltmeter into it to monitor voltage and eliminate a possible sticky fan.
Ran the fan on low a few minutes, up to #2 for same, and to #3. On #3 for a minute and saw the voltage drop to zero on the voltmeter. Let it sit, no action at voltmeter.
Yanked repro relay and ran a jumper across the connector. On #3 and ran for 15 minutes, went through the switch speeds, seems OK. all wires cool, voltage at fan motor connection the whole time. (Gotta be that relay)
Stopped at surplus store on way home, grabbed a 30A generic 12V relay that looks like it should be on a 1986 Pontiac 6000. Hooked this thing into the A/C relay connector (green wire ground, black activator, blue is hot-----nice color picks)
Seems to be working great with the relay installed, power at fan connector, no hot spots, work through the switch, no outage.
Next step is to go for a drive, actually run fan, and engage A/C to see if I can get some runtime.
New fan, NOS 481794 relay and AC harness on the way, but I am thinking new relay may do the trick.
Wow, you sure learn a lot on the electrical system on these things when you are trying to figure out gremlins, the simplicity and straight forward engineering concepts is awesome to follow.
Thanks for tips, will see what happens tonight

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  #6  
Old 08-18-2022, 10:13 PM
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Late update, been away a couple weeks.

Looks like it was the relay. The generic one worked and continued to work for a 3 hr trip during vacation and is working great. Got the new harness and a replacement relay, will install those once I get a minute. Got a new blower motor, will keep that in the trunk for spare.

Thanks for replies.

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