Heater Blower Motor

[Greg C.]

So I routinely start the coach up once a week and let it run until it reaches operating temperature. It's in the 40's here right now, so I usually run
the heater blower on high.

I know that the high position only runs on high when the alternator is producing power.

My medium speeds are the same as off/low, so I know my resistor is most likely bad.

But tonight, while the blower was on high, I turned it to low to listen to the engine for a bit. When I turned it back to high, I no longer have high
speed. My alternator light works, and it wasn't lit up, so I

am assuming that the alternator didn't die at the exact instant I turned the fan to high.

Where should I look first?
--
Greg Crawford
KM4ZCR
Knoxville, TN

"Ruby Sue"
1977 Royale
Rear Bath
403 Engine
American Eagle Wheels
Early Version Alex Sirum Quad bags

 

[john r. lebetski]

77 has a high delay relay. You have to wait after selecting high with engine running. That delay relay may have failed. You can easily patch around
it no cutting as it was new for 77
--
John Lebetski
Woodstock, IL
77 Eleganza II

 

[john r. lebetski]

Your practice of starting and running in park puts combustion water in the oil every time you do it. Without driving, the oil won’t exceed 212F to
boil off and be removed by PCV. The acidic water produces sludge.
--
John Lebetski
Woodstock, IL
77 Eleganza II

 

[Greg C.]

Yes, I understand that idling will not get the oil hot enough to burn off moisture.

I do drive it down the road occasionally as well to exercise everything.

I'm waiting for a weather break ( I have to work outside) to pull the radiator and change the timing chain, water pump, belts, hoses, etc. and I will
change the oil again at that time.

--
Greg Crawford
KM4ZCR
Knoxville, TN

"Ruby Sue"
1977 Royale
Rear Bath
403 Engine
American Eagle Wheels
Early Version Alex Sirum Quad bags

 

[Matt Colie]

> So I routinely start the coach up once a week and let it run until it reaches operating temperature. It's in the 40's here right now, so I usually
> run the heater blower on high.
>
> I know that the high position only runs on high when the alternator is producing power.
>
> My medium speeds are the same as off/low, so I know my resistor is most likely bad.
>
> But tonight, while the blower was on high, I turned it to low to listen to the engine for a bit. When I turned it back to high, I no longer have
> high speed. My alternator light works, and it wasn't lit up, so I
>
> am assuming that the alternator didn't die at the exact instant I turned the fan to high.
>
> Where should I look first?

Greg,

Find a piece of wire and rig a run straight from the starter battery to the fan terminal. Fan motors this old fail all the time. Replacement is easy
and inexpensive.

It could be the resistor set too, the rivets get loose with age. Sometimes I have been able to reset them, but that has about a 50% success.

I have only seen one of the delay relays fail, but I am sure that they do.

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

 

[Greg C.]

Per Matt's suggestion, I went out to the coach today with a jumper wire and found the high blower relay. When I jiggled the plug, the fan went to
high. Just another case of corrosion on the contacts I guess.

Something else to clean.

Then I took the coach for a 20 mile warm up ride.
--
Greg Crawford
KM4ZCR
Knoxville, TN

"Ruby Sue"
1977 Royale
Rear Bath
403 Engine
American Eagle Wheels
Early Version Alex Sirum Quad bags

 

[john r. lebetski]

Great! And that’s why GM eventually went to weatherpak connectors. I clean the ones at the hi relay and the resistor network yearly with D5. Helps
prevent meltdown on those connectors from resistance heating. Common GM problem also found on other makes.
--
John Lebetski
Woodstock, IL
77 Eleganza II