heating question

[grunt11b40x]

first my blower motor will come on some time and other times it will not, no problem I can bypass the switch but even when it does come on I do not get any hot air through the defrost, only cool air. my switches are moving and the cables are working. does anyone have an idea of what could be keeping the warm air from coming through? 75 blazer used to have AC, but commpresser is removed don't know if that would have anything to do with it. /forums/images/graemlins/confused.gif

 

[or2play]

You may have a loose wire on the blower motor. It should come on any time the key is turned on. Even with your blower switch off. Having the a/c compressor off will not affect anything. I don't have mine on either. As long as everything else is hooked up electricly and your vacumm line is hooked. If you can get any hot air at all, the cable may not be moving the door inside the heater duct. I'd also check the heater core to make sure its not pluged or anything like that.

 

[grunt11b40x]

vaccum lines hmm that may be a problem , what function does the vaccum play in getting the heat flowing?

 

[mudjunkie 82]

Could be a vaccum line to the hot water valve, also the fresh air damper on the cowl could be stuck open /forums/images/graemlins/thinking.gif

 

[or2play]

On a a/c equiped system the lever that selects what vents the air flows out of, ( a/c, vent, bi, heater, defrost) that runs off vacuum. There should be a hose going from your intake manifold to a round little bowl thing on the firewall right above the blower motor. Its like a accumelator, supplys vacuum to the selector box in the cab.

 

[99firehawk]

Being that I just rigged........er fixed my heat Ican tell you excatly what to check. First thing is the engine getting warm? Next is there enough coolant in the engine. With engine warm feel the hoses going into the firewall, both should be hot if one is hot you have a plugged heater core. Next open your glove box and fold it down. You will see 2 door controls, the one closest to you is the floor/vent door. The one farthest from you is the cold/heat door. Make sure when you put the truck to heat this one moves. Now from the drives side reach up under the radio and un plug the vacum line from the diaphram there put a 2-3 ft piece of vacum line on it and start up the truck, now suck through the vac line and see if you get hot air then. If you do then the prob is in your vacum lines, if you dont you need a defrost door diaphram. good luck, If you cant figure it out pm me and Ill mail you what you need to rig...er fix it


also if your blower motor is on and not working leave it on pop the hood and take a ratchet and smack the motor if it comes on then you need a new one.