Dash fan has only hi speed

[ktcnyc]

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

 

[Matt Colie]

Kevin,

That means that either the switch or the resistor is bad (maybe both). But the resistor is easier to get to. It is in the left side of the HVAC case
and has a multi-wire plug on it. If pulling and pushing that that plug doesn't get it, try measuring resistance between all the terminals and most
likely one is open. Those resistors are cheap and real available.

Hope it is not the switch.

Matt
--
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit

 

[Ken H.]

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.

> 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:
>

 

[Ken B]

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