AC Blower fix
Junior Member
Joined: Sep 2013
Posts: 5
Oops
So after finding this post and replacing the resistor and harness w/no a/c still it ended up being a 15.99 a/c relay switch located on the fan itself. Fan is ok, system works now; ended up replacing harness, resistor, and RELAY. System worked after relay was installed. Possibly all 3 were the issue, possibly just the relay. Relay is 15.99 at autozone. Try obtaining parts as Colorado parts to save money. It's the same stuff. Cadillac charged me 112$ for harness and resistor.
Good luck fellow Hummer lovers!
Joe Perkins
Good luck fellow Hummer lovers!
Joe Perkins
Junior Member
Joined: Sep 2013
Posts: 5
Whatever you say dude
I had already replaced the harness and resister, put it all together, and tested it before I bought the 15.99 relay. After replacing the harness and resister I tested the connector to the fan and had voltage but no fan movement. I took the fan out, spliced some wire to the battery and retested the fan motor and it took off. That left only 1 thing to replace, the relay. After replacing the relay it works fine. Before it was d e a d at all speeds. I'm not an automotive electrical specialist I'm an asst surgeon. By process if elimination it was the only part not changed, and the fan motor definitely worked when energized. The part is 15.99, gasoline is 3.60 a gallon, frustration and scratched up hands/arms are priceless to avoid; I'd recommend changing it while anyone is doing the other 2. Yes, the harness and resister were burnt, especially in right side prong area on both; however, it wasn't till I'd made another trip to Autozone and replaced that cheap part that my hvac system started blowing air again. An ASE certified mechanic told me the relay diagnosis and symptom of only highest speed working; NO speeds worked until all 3 parts were replaced. Was fine one minute, stopped somewhere, turned the truck off, and when I came back the blower was dead at all speeds. No prior issues with any or at any particular settings, just dead. 15.99? Swap it too while you're at it. After changing the 1st 2 parts I'd tested the wire to the fan while relay connector was still connected and it was getting voltage. Did not disconnect relay for that test, when the entire thing was out of the truck, no resistor connected, just straight to the battery and it took off there was only 1 part left to mess with and changing the relay fixed it. It's possible it was just the relay, and it's possible it was the already heat damaged harness and resistor. It's certain that the system didn't work again until all 3 were replaced though, and it's a fact that multiple trips to parts stores suck booty bad; that's why us recommend doing all 3 for 15.99 more- after confirming the fan will respond to voltage.
Senior Member
Joined: May 2012
Posts: 2,005
ok im glad it works. I guess my 2 service manuals and the downloaded diagram are wrong huh!! thet show the resistors going direct to the motor asnd the relay getting turned on in the last position. it should work without it
just for fun ill pull my relay and see if the low speeds work and report later. im betting 15$ it works!!
don't know how to copy diagram,darn
just for fun ill pull my relay and see if the low speeds work and report later. im betting 15$ it works!!
don't know how to copy diagram,darn
Junior Member
Joined: Sep 2013
Posts: 5
That's what I didn't try.
ok im glad it works. I guess my 2 service manuals and the downloaded diagram are wrong huh!! thet show the resistors going direct to the motor asnd the relay getting turned on in the last position. it should work without it
just for fun ill pull my relay and see if the low speeds work and report later. im betting 15$ it works!!
don't know how to copy diagram,darn
just for fun ill pull my relay and see if the low speeds work and report later. im betting 15$ it works!!
don't know how to copy diagram,darn
Junior Member
Joined: Sep 2013
Posts: 5
Curious
Hey, says ur a sr member? What's the rubber hose for from the fan housing to a port about 9"s away? Something definitely was pulling hard to fry all the connectors; has the underlying reason of burning been determined by anyone? Could the fan be trying to pull too much volts/amps and burning the parts. On mine everything was visually burned including the prongs on the relay I think. The fan motor is 90$ at autozone and 190$ at dealer FYI for fellow hummer owners.. Has anyone on here tried the flexfuel kit for Hummers? If so plz give feedback.
Junior Member
Joined: Aug 2013
Posts: 3
Common Hummer H3 Blower Problem
Does the AC light still come on but no air blows out?
Did you notice a burning smell just before the blower stopped working?
You may be a victim of a poor Generous Motors design for controlling blower speeds. With the technology available when Hummers were first made, it seems strange that GM did not implement a PWM system to control the blower speed in Hummers. That system would save energy, not produce heat like a resistor, to control the blower speed. It would have also allowed GM to put a continuously variable speed control on the Hummers for their customers, instead of a four speed switch.
Anyway, they didn’t do it, probably to save a few pennies per Hummer. So those of us who have had to put up with the failure of our blower system, have to dish out big bucks for getting our blowers working again. The repair is not a fix, because IT WILL FAIL again.
Now, you may be able to save those big bucks if you are half way handy with a soldering iron and a Dremel type tool. This may also prevent your blower speed control from failing again.
I assume you know the H3 blower motor and wiring harness is located behind the glove box. Remove glove box to start this project. Remove right end cover to dashboard. Remove blower plug, remove white gang plug, remove black gang plug, THEN remove resistor with connector attached last. Now take resistor and wiring harness to your work bench to start saving more money.
You may have to work to get the resistor removed from the connector as the burnt terminal inside has melted and fused the surrounding plastics together. Keep working at it, rock it back and forth, you will get it apart.
Now, does it look something like this?
Cut around the connector shield on the resistor to allow better access to the terminals. You can cut this with a Dremel type tool or with wire cutters like I did.
Now you can use a file, sandpaper, or a Dremel Type tool to clean and roughen up all the resistor terminals. This will allow the solder to better adhere to the terminals and give you a better connection. We don't want any cold solder joints here.
ANext, cut the wires behind the connector on the harness so as to get us into some fresh, unburnt wire.
Take note of the wire colors and orientation at this point. We want all wires going back to their original terminal.
Carefully solder each wire to its corresponding terminal, making sure your soldering iron is strong enough and hot enough to make a good clean solder joint on each wire and terminal.
Reinstall the harness back into the vehicle first, and reinstall the resistor last. This will prevent any excess strain and pull on the resistor terminals.
Turn the key on and enjoy your AC blower once again! And it cost you nothing but time. If you made good solder joints, your blower should never fail again!
Good luck!
Craig
Thanks,
Chris
