Heater and ac fan won't work 1999 Chevy S10 4.3L

SOURCE: 1999 honda accord ac / heater fan control

Hi! The speed control is defective.The terminal 1&2 could either b worn or burnt out.

SOURCE: BMW 328i AC Not Cooling

Check the temperature control box.

Mark Lewis

• 105 Answers
• Posted on Jun 05, 2010

SOURCE: need to replace ac/heater fan resistor

The Blower Motor Resistor is located on the passenger side firewall, not far from your A/C's H-Valve (or expansion valve), going inside of the vehicle. The blower motor resistor has a 4 or 5 way black connector plugged into it and this is the only visible portion of the Resistor you will see. Remove the wiring connector and remove the 2 or 3 screws with an 8 mm or 5/16" socket (8 mm and 5/16" are the same). Once the screws or fasteners are removed, just pull the blower motor resistor out of the firewall and if you look at it, it will have various coils of wire on it, sometimes it will show burnt coils, but you can always check the various coils with an Ohm-meter.

Aside from that, install the new Blower Motor Resistor and Voilà! Your inside Blower Motor should work just fine.

A brief note here, if your fan doesn't work when the fan switch is on High, then it's not the Blower Motor Resistor, but possibly the Blower Motor itself. Should this occur, please get back to me insofar as how to replace the blower motor and why the blower motor's wires have to be twisted...even with the new blower motor fan.

Best of Luck,

"00 Buck"

"Still living on the Right Side of Dirt..."

SOURCE: I have a 1999 Jeep TJ. My heater recently stopped

Hello Tom,
This problem can be trouble shot by checking: The fuse. Are you 100% sure it is good? Get a new one unless you are sure. You said you replaced the resistor but still check it again to be sure it did not cook recently. It will appear crusty,melted carbon deposits. If you bought a good NEW heater motor check it again by getting or making some cheap jumper leads and by unplugging the heater connector under the hood, connect one of the leads to the battery then to one of the posts of the heater. Connect the other jumper to to the other post and to the connector on the motor. It should whirl around and scare the heck out of you it you get the polarity right : ) now, onto something more fun and where I think your problem is. Your control panel.... Using a phillips screwdriver, remove the screws from your face plate/facia/dash moulding covering your stereo/climate control panels. Screws located under eye glass basin,in back of cigarette ash bin and below I think. It pops off and exposes the screws to your climate control module. 4 screw/nuts allow you to pull out your climate module box. Check your connections. Most likely, your selector switch is melted. Perhaps even the harness that plugs into it is melted too. Replace the blower selector switch (small screw removes it) with a new one. Autozone carries them. If your wiring is toast, make a drawing of your color wires BEFORE you cut them free (what post on the switch the wire plugged onto by aligning the plug orientation to the post orientation "mated connections") and close to the connector as possible making sure the wire is good. Get some heavier gauge wiring and splice in and solder neat and strong extensions onto the cut wires. While you are at your auto store, pick up the appropriate female plug in connectors to fit over the blower speed selector pins. Solder these onto your extensions as well and liquid tape all bare wiring. Plug them onto the correct plug to the blower motor switch. YOUR VERY DETAILED DRAWING that you made. When I did this, I made my wire extensions about 8 inches long so I had plenty of room to solder and work. Check your connections,tape them to avoid shorts and use liquid tape on the blower speed connections if there is bare wire. Turn your vehicle on run through your selector speeds. You should also replace your RELAY. It is located on psngr side under glove box. Buy a good one. Replace this even if it appears to be working as they can get worn and as your motor gets worn, allow extra juice to backfeed and kill your heater components again. I hope this helps. If all of this fails your wiring harness may be cooked but I think this is your blower speed selector switch. I will be on here to check on you the next few days to see if you need any more help. Let me know how things turned out so I can help you more if needed. This is a very common problem with this model. Take care.

SOURCE: 1999 Chrysler 300m heater won't get hot fan

Is there enough anti-freeze in the system?
If so perhaps the system needs bleeding.
On the front of the engine, on top near the big upper hose goose neck and nestled between the runners of the intake manifold is a small nipple that looks like a brake bleeder (10MM). This is a cooling system bleeder, a close cousin to the brake bleeder. When opened it will purge the system of air- likely the culpret you are experiencing. on a cold or just warm engine, this can be slightly opened with a wrench and the air can be "Burped" out. Attach a 1/4" clear hose to the nipple and open the bleeder until you see all the air has left the manifold. (Run the hose into a bucket and dispose of the used anti-freeze properly.)
if that doesn't do it, maybe the thermostat is stuck in the open position. Replace it with a cold engine and use a new gasket each time.
If all else fails, the heater core may be plugged.