93 suburban: Heat only when moving/no fan in front/back cold too

[SilverSea88]

I have a '93 Suburban, Its actually in great shape, except that the fan made some loud whining noises for about 45 minutes and doesnt work at all now. I have heat, but only when Im driving on the highway and only when the heat is actually turned to the "off" postion on the switch and I dont even have heat when slowly driving around town. The rear fan works, but blows cold too. Im not sure that even gets hot when Im moving, as I feel a cold breeze on my neck when I turn on the fan when Im driving. I dont think the ac works at all...just bought this truck, so havent tried it, and its cold out anyway, so I'll have to wait I suppose.

Anyone know how to fix this?...thanks!

[j cAT]

since you just purchaed this and you have coolant issues replace the coolant. 1993 will use the green type coolant.

drain the system and disconnect the heater core hoses at the ENGINE.

then flush out the heater core with a little pressure using a water hose. slowly at first because it is very possible its restricted. then if possible blow out any remaining water.

replace the thermostat. most times after 4-6 years these get stuck. do not fully close then you get what you have now.

If possible drain engine block.

use distilled water with the coolant so you put in 60 % coolant to ,,,, 40 % distilled water.

prestone now has extended life coolant 5yrs that is the green NON DEXCOOL type. I have used this on some older vehicles like yours and it is very good. walmart has it cheapest I could find.

[SilverSea88]

It worked fine until the blower stopped, and this truck has been meticulously maintained since new...so I think the real problem is in the switch, a fuse, or in the blower motor itself...I do have heat and actually alot of very hot heat, but I cant control it, its only when moving. Thanks!

[j cAT]

Originally Posted by SilverSea88

It worked fine until the blower stopped, and this truck has been meticulously maintained since new...so I think the real problem is in the switch, a fuse, or in the blower motor itself...I do have heat and actually alot of very hot heat, but I cant control it, its only when moving. Thanks!

being a 1993 my guess is the blower is shot. first check the connector to the blower grid resistors. then with a voltmeter at the blower connector with the blower connected check for voltage ...if the voltage is there and the blower does not work its defective. go to scrap yard to see if you can get one cheap but look first for new motor availability and models that used this same blower.

no blower at any speed is the blower motor , fuse, connectors.

with a meter this is an easy task to find the cause.

on the newer vehicles they use cheap crap circuit board resistors that fail just after warrantee ends.

[SilverSea88]

That sounds pretty dead on...I'll try that! Thanks alot!

[SilverSea88]

Oh, btw, do you know where the fuse is located so I can check that first?...Thanks!

[j cAT]

Originally Posted by SilverSea88

Oh, btw, do you know where the fuse is located so I can check that first?...Thanks!

not exact on your model . I would think its the driverside of the dash next to the driver door.


I just replaced a blower on a 1994 chevy S10.