A/C won't switch to heat

[tam5070]

hey ok before i have the mechanic look i wanted to see if you guys had ideas... I have a 98 s-10 v6 vortech... Anyway recently the summer and such ive been using ac alot so its been fine. But recently when i went to use the heat (hello colder weather) i found that not only did the air not get hot, but that it was still blowing ice cold even with the engine warmed. Its the point where i have trouble driving because the window becomes frosted and i cant see. Additionally, the 4th fan setting doesnt work when you try to turn it from 3 to 4, but this problem ive just dealt with. My friend said it might be an actuator or something, but ive never had this problem before.

Any Suggestions are appreciated!

[mrmidnight]

Could be the switch, wish I could tell ya how to troubleshoot that, but AC isn't my specialty

[Mikz86TA]

1st off Welcome to The PLANET!! 2nd, is the Fan knob just not going to the 4th setting or is 4th just not blowing any harder? 3rd, when you switch the controls around, do you hear the doors behind the dash opening/closing?

[tam5070]

the fan switch goes to four but th eblower stops. im not sure abou hearing it switch, ill try and listen and post back.

[tam5070]

i asked a friend and after we took out some of the lower dash he said its probably my actuator. i can see it under the dash on the drivers side. How easy is this to swap out and how expensive can i expect the part to be?

[Mikz86TA]

The blower is a fuse or hi-relay. The fan works like this: There is power going to the fan by 2 sources. One is a direct hi-volt source through a relay that gives the fan full voltage for its highest speed. The other is through a thermal resistor which reduces the voltage to the fan and gives it the lower 3 speeds. The blower motor relay is under the hood. The power for the hi-speed is from the underhood Fuse 30Amp under the HVAC slot. Blower relay is activated by the wire coming off the back of the AC controls and is the ORANGE wire. Test with a meter here 1st to start off with. If there is no voltage out of the Orange wire (back of AC switch panel) then replace the AC switch panel. If voltage is present there when on HI, move on to checking the fuse and relay. If relay is suspected to be bad (it rest in the low position) then swap another relay in temporarily from another spot to check. The AC Blower relay is a 5-pin relay. At the fuse panel under the hood is 2 styles of relays....a 4-pin and a 5-pin. Relays usually are Omron brand and will have that logo and part # on the top. Get back after you check this out. =)