| Dash fan has only hi speed [message #364732] |
Tue, 15 June 2021 18:12  |
ktcnyc
Messages: 25
Registered: September 2020
Karma: -1
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Junior Member |
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Hello - my coach has only hi speed on the heater/ac blower. It has a new fan motor and relay. Nothing happens on lo and medium.
Any guidance will be greatly appreciated
Kevin Cloutier -'77 Eleganza II-455, 6 disk brakes, Edelbrock carb, headers, , resident of NYC and Dingmans Ferry, Pa.
'72 MGB-GT & '73 MGB convertible
Member GMCMI since 8/20
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| [GMCnet] Re: Dash fan has only hi speed [message #364734 is a reply to message #364732] |
Tue, 15 June 2021 19:00  |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Kevin,
The HVAC blower runs, in the lower switch positions, through the resistor
pack mounted in the left side of the HVAC box, beneath the driver-side
hood. In HI, it bypasses that resistor and runs directly on alternator
output voltage. You can see all this clearly on the coach wiring diagram
in the back of the maintenance manual.
Check that resistor pack -- do sometimes fail, though rarely..
Ken H.
On Tue, Jun 15, 2021 at 7:13 PM wrote:
> Hello - my coach has only hi speed on the heater/ac blower. It has a new
> fan motor and relay. Nothing happens on lo and medium.
> Any guidance will be greatly appreciated
> --
> Kevin Cloutier -'77 Eleganza II-455, 6 disk brakes, Edelbrock carb,
> headers, , resident of NYC and Dingmans Ferry, Pa.
> '72 MGB-GT & '73 MGB convertible
> Member GMCMI since 8/20
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Re: Dash fan has only hi speed [message #364735 is a reply to message #364734] |
Tue, 15 June 2021 19:43 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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Another thing to check is the connections at the relay. They sometimes burn open. Look closely at the relay connections / terminals and also the resistor terminals for signs of burning.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: Dash fan has only hi speed [message #365606 is a reply to message #364733] |
Wed, 21 July 2021 13:59 |
ktcnyc
Messages: 25
Registered: September 2020
Karma: -1
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Junior Member |
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Hi Folks- Following up on my dash fan - I have a new fan motor, new relay and I just installed a new switch. I pulled the peculiar flash gordon resister gizmo out and cleaned the plug and connection -Still doesn't work. Is there an update on that gizmo and do you know where I would get a new resister pack?
Many Thanks, Kevin
Kevin Cloutier -'77 Eleganza II-455, 6 disk brakes, Edelbrock carb, headers, , resident of NYC and Dingmans Ferry, Pa.
'72 MGB-GT & '73 MGB convertible
Member GMCMI since 8/20
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| [GMCnet] Re: Dash fan has only hi speed [message #365613 is a reply to message #365606] |
Wed, 21 July 2021 17:32 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Kevin,
You probably took care of this, but just in case: The fan motor gets its
ground via a jumper wire from its case to the body ground, bypassing its
rubber isolation mounts. Those tend to loosen and lose contact. Try using
another jumper wire from bare metal on the motor housing to a known good
ground.
Failing that, it's time to get a test light or multimeter out and start
following the voltage from the fuse, through the switch, etc., etc.
Ken H.
On Wed, Jul 21, 2021 at 2:59 PM wrote:
> Hi Folks- Following up on my dash fan - I have a new fan motor, new relay
> and I just installed a new switch. I pulled the peculiar flash gordon
> resister gizmo out and cleaned the plug and connection -Still doesn't
> work. Is there an update on that gizmo and do you know where I would get a
> new
> resister pack?
>
> Many Thanks, Kevin
> --
> Kevin Cloutier -'77 Eleganza II-455, 6 disk brakes, Edelbrock carb,
> headers, , resident of NYC and Dingmans Ferry, Pa.
> '72 MGB-GT & '73 MGB convertible
> Member GMCMI since 8/20
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: Dash fan has only hi speed [message #365614 is a reply to message #364732] |
Wed, 21 July 2021 19:49 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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Without a meter, this is getting to be like Facebook advice—- guessing.
All speeds go through the relay. Deenergized it passes the 1, 2, 3, voltage to the motor on the normally closed contacts. Energized (hi and engine running) the relay contacts flip to the normally open contacts and pass alternator voltage to motor. You did not replace the resistor pack. You could inspect and meter each wire coil to pins to confirm some Ohm reading not open. Also the new relay or old resistor may still not be making contact at the old oxidized connectors. I spray all that with Caig D5 before plugging in and sometime you STILL have to wiggle them to get them to work. That’s why GM went to Weatherpak connectors in the years after our coaches. Try the meter Ohm tests on the resistors and then the wiggle method. If that fails you need to meter voltage per schematic source to motor.
John Lebetski
Woodstock, IL
77 Eleganza II
[Updated on: Wed, 21 July 2021 19:51] Report message to a moderator |
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