2006 Trailblazer doesn't blow on speed 5

My wife told me that the Ac wouldnt blow on speed 5 but all of the other ones still work, so i did a little research and found where the resistor was and decided to check that out after i looked at all the fuses. Fuses were fine and when i took out the resistor i noticed that the ground wire and the power wire for speed 5 were fried and had melted plastic on them. So i figured i would change the resistor and it would be fine since i was still getting the right voltage coming from all seven of the wires that plug into the resistor. After installing the new resistor, i tested it and it seemed to work fine. After running it on 5 all the way to pick up my daughter, i shut the car off and upon restarting it.... SPEED 5 DOESNT WORK!!!!! Any one have ideas what could be the problem.

Check for applicable trouble codes, manufacturer specific as well as generic. There are some trouble codes for the hvac. We need something to point us in the right direction.

Where would I find these trouble codes, I was also told it could be a faulty blower motor or the actual ac control dial deal. Also I forgot to mention this is a manual ac unit

When the blower relay is energized, only continuity for high-speed. When the relay isn't energized, continuity for other speeds, not high.

The coil side of relay, squiggle lines, has to have voltage and ground to energize relay. When relay is energized, that line with the arrowhead moves to other terminal. At the coil side of relay, black wire is chassis ground, constant ground. Orange wire is voltage for coil side of relay, comes from hvac control module.

The data link connector should be lower left side of dash, 16 pin connector. I can't say if codes will be any help, just a possibility.

The red wire, in diagram, is voltage for high-speed only. Fuse 35-- 40 amp underhood fuse block, hot all the time.

Did you replace the burnt terminals or just the resistor? It is not the blower motor or no other speeds would work. You most likely need a connector pigtail for the resistor if you plugged the melted one back in.

Yea I plug the melted one back in since it was still getting the right voltage when I tested it and since the blower turned on. We were about to head outta town so I didn't think it was a big deal. I look at it again as soon as I get a chance. I have to replace the water pump and fan clutch ASAP. So this is going to take a back seat for now. And if I replace the pigtail, should my resistor still be ok. Thanks for the info guys

Check for applicable trouble codes, manufacturer specific as well as generic. There are some trouble codes for the hvac. We need something to point us in the right direction.


How is resistor switch in the dash going to throw a code? :eek7:


Yea I plug the melted one back in since it was still getting the right voltage when I tested it and since the blower turned on. We were about to head outta town so I didn't think it was a big deal. I look at it again as soon as I get a chance. I have to replace the water pump and fan clutch ASAP. So this is going to take a back seat for now. And if I replace the pigtail, should my resistor still be ok. Thanks for the info guys


What you need to find is what caused it to melt in the first place, and why it was able to get so hot with out blowing a fuse.

Best guess is something must be shorting somewhere.
I wouldn't run it on speed 5 until you find that short.

This is a VERY common problem. The resistor cards can't handle the current so they overheat, melt, and peel apart. There is even a T.S.B. on it for this vehicle and an extented service policy on some vehicles extending the warranty or reimbursing customers that paid to have the repair. You need to replace the connector, and may have to clean the affected terminals on the new resistor. You don't have to cut and splice all seven wires if you know how to remove the terminals from the connector body, just transfer the good ones to the new connector and splice the 2 or 3 bad ones. Your voltage measured good because a meter does not present any load to the circuit.

This is a VERY common problem. The resistor cards can't handle the current so they overheat, melt, and peel apart. There is even a T.S.B. on it for this vehicle and an extented service policy on some vehicles extending the warranty or reimbursing customers that paid to have the repair. You need to replace the connector, and may have to clean the affected terminals on the new resistor. You don't have to cut and splice all seven wires if you know how to remove the terminals from the connector body, just transfer the good ones to the new connector and splice the 2 or 3 bad ones. Your voltage measured good because a meter does not present any load to the circuit.



Fantastic!

You don't get a better answer than that :smokin:

Hope you folks didn't see my last post, it was inappropriate, I deleted it. Haven't had my morning coffee, yet. good day

Has this concern been resolved? Have you brought this to the attention of your local dealer? I can also look into this issue further. In order to do more research, I will need some more specific information from you such as your name, address, phone number, the VIN for the vehicle, current mileage, and dealer name. If you have further questions, please feel free to contact me either on the thread or via private message. Thank you.

Tricia, GM Customer Service.

Hope you folks didn't see my last post, it was inappropriate, I deleted it. Haven't had my morning coffee, yet. good day



No worries mate. It's amazing what a bit of caffeine can do for your mood :smokin:


I don't know a lot about American cars, although I drive one, it's got a Honda badge on the front. The only American cars we get here in any quantity are wide body Accords and Camry's. Everything else comes over from Ausie, out of Japan or from Europe.

But, we're finding that being active in threads is helping get more members involved.
If I say something stupid, hopefully it promotes someone who does know what they are talking about to come in and correct me, and that usually leads to a solution.

It's all about the community :cool:


klguy77

It does sound like procaddytech has the problem sussed.
We have also confirmed, to the best of our abilities, that Trish does indeed work for GM.
The fact she posting here would also back up procaddytech summary of the problem, and it may also mean the part can be fixed under an extended warranty, or recall.

Hey that's great. I've been told posters like diagrams. So I explained it. good day.

Has this concern been resolved? Have you brought this to the attention of your local dealer? I can also look into this issue further. In order to do more research, I will need some more specific information from you such as your name, address, phone number, the VIN for the vehicle, current mileage, and dealer name. If you have further questions, please feel free to contact me either on the thread or via private message. Thank you.

Tricia, GM Customer Service.

Not yet, I just finished putting in the water pump and fan clutch yesterday. Ill be busy the rest of the week but come the weekend im going to get this fixed. Not sure if the dealer will be able to do anything since I bought it used from a private seller. Truck has about 66k on it

You need to either splice in a new connector or shim the pins...my 2005 TB did the exact same thing and I shimmed the ground and "#5" pin. To shim it I cut a small piece of aluminum (very small in fact, needs to be able to fit inside the connector on the female side so it makes better contact with the male pins when you push them back together). Works fine now...