Unwanted heat

[Chumley]

Anyone know why I have heat coming out of my vents when the heater is off? I suspect that vacuum controlled valve under the hood that goes into my heater hose. I also have air but it has been inoperative for at least 15 or more years. Any connection between this and the heat problem? Also the fan motor is not working, even after replacing the switch. Now I suspect the heater relay which is way under the dash somewhere. I'm certain the motor works, because it kicked on for just a couple of seconds while I was jimmying wires around under the dash. Any input? Thanks............Chumley

[Sams_71]

Chumley,

I had the same problem, heater was blowing heat in this 100 degree weather. Couldn't handle it anymore and went a little overboard http://classicheartbeat.com.westserver.net/ubb/redface.gif I replaced everything that had to do with the A/C so I could get it working again. I'm no expert but, it might be that heater valve under the hood. Mounts on the wheel well, has a vacuum line and radiator hoses running through it. Seems to me that if hot water gets rerouted back to the radiator and doesn't go to the cab you won't get hot air.

Just my $.02,



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Sam

http://home.att.net/~tmj39/wsb/html/view.cgi-home.html-.html
tmj39@att.net

[jwill41]

I installed a shut-off valve in the heater hose to cure this problem.

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67 gmc short step side
68 chevy long fleet side
88 chevy 3/4 ton suburban
97 chevy short stepside
Farmers Branch, Tx

[longhorn man]

As for your heater motor, the relay only controls high, the rest of it goes through the switch.

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'69 G.M.C. (http://geocities.com/andys_69_gmc/) 350/350 and a heluva cam. Still trying to clean up the left over damage from the Dope-Smokin-Old-Man.
The 1970 One ton Longhorn (one of only 1404 built) with only a TH350...soon to be CADDY powered and a TH350. Check out The Longhorn Webite. (http://www.longhorntrucks.freeservers.com/) Andy, in Columbus Ohio...Home of JEGS

[Protrucks]

I too put a shut off valve in the heater hose going to the heater core. Far as I know it is the only way to stop it. It really helped out one time when the core went out on me 60 mile from home, so make sure to put it on the in coming side of the core for this extra protection.

[longhorn man]

This is something I have been wanting to do. I know hapa has a nice looking little piece for this pourpose for 20 bucks. i just installed one on my dad's Lincoln.

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'69 G.M.C. (http://geocities.com/andys_69_gmc/) 350/350 and a heluva cam. Still trying to clean up the left over damage from the Dope-Smokin-Old-Man.
The 1970 One ton Longhorn (one of only 1404 built) with only a TH350...soon to be CADDY powered and a TH350. Check out The Longhorn Webite. (http://www.longhorntrucks.freeservers.com/) Andy, in Columbus Ohio...Home of JEGS

[longhorn man]

hapa??? Ok, lets try checking N.A.P.A. http://64.246.42.114/vboard/images/smilies/rolleyes.gif

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'69 G.M.C. (http://geocities.com/andys_69_gmc/) 350/350 and a heluva cam. Still trying to clean up the left over damage from the Dope-Smokin-Old-Man.
The 1970 One ton Longhorn (one of only 1404 built) with only a TH350...soon to be CADDY powered and a TH350. Check out The Longhorn Webite. (http://www.longhorntrucks.freeservers.com/) Andy, in Columbus Ohio...Home of JEGS