2004 fan speeds not working

I got this truck a year ago and the fan speed never worked right but it blew in high speed so I never really cared. But now it doesn't blow in high anymore and I need it to defrost the windshield. Up until the other day 1-4 speeds blew out like it was on 1, and then I had 5 speed which blew out fast, then there is the off. Now it blows slower than 1 in all ranges but off. Has anyone else had this problem? Do I need a new climate control unit, or is there something else to look for?

Thanks for any input

P.S. I have the manual climate control unit if that helps.

you have in most cases the resistor failure ,,,and because the blower NOW don't work on high could very well be the blower motor esp....if you continually used the max speed..removal and inspection is required ...then post back any questions..these parts are available at the local auto part stores...every one of these have failed...at this age..also make sure the air box filters are replaced,,these will provide protection to the ac evap unit and prevent air restrictions..removal causes problems down the road..

the resistor/relay control device at the blower motor is about 25.oo........

After I posted this I looked through other threads and read about the resistor. So I just ,a little while ago, took it off and it is definitely fried. Just in the last week the high speed has been working at times and not at other times. Like last night it didn't work but it did this morning. Also where are these air box filters located? And is the relay a GM part or can I get it anywhere? What should I look for on the fan, should I see something that is burnt?

Thanks for the help.

I have changed the resistor on these and also GM cars, about 10% it has actually been the switch on the dash, and there have been times when it has been both. I think in the times it has been both that the resistor was out long enough to do harm to the switch. the switch itself can be bought at the dealer without buying the whole thing. I dont know for sure what year the switch started to be a whole unit instead of being taken apart. but if you take it out of the dah you will be able to see if they come apart the part number for the single switch is GM#19131601 it runs about $20.

After I posted this I looked through other threads and read about the resistor. So I just ,a little while ago, took it off and it is definitely fried. Just in the last week the high speed has been working at times and not at other times. Like last night it didn't work but it did this morning. Also where are these air box filters located? And is the relay a GM part or can I get it anywhere? What should I look for on the fan, should I see something that is burnt?

Thanks for the help.

the air filter is in the air box to the left of the resistor/blower motor assy...there is a slot with a screw locking the plastic retainer that securely holds the 2 piece white cloth filters in place, about 2 inches from the resistor assy....
the resistors if OEM will disintergrate, then you gradually loose speeds...the blower motor can draw too much current when it is failing so you want to make sure the blower is rotating freely /not binding...then if the resistors replacing gets it to work make sure its not running hot then starts to bind up...

with the switches these can fail,,it is possible...not a high failure item...but if you switch the speeds continuously then the switch in your case could be shot...using a meter and inspecting all this is not that difficult and when the cost/time lost bring to a dealership is considered its worth your effort...

I took the blower motor out and it spins freely, but can't test for heat till I get the resistor. I looked for the filters and to the left of the resistor is the heater core. I can see it through the slot the resistor went into, and there is a solid plastic case around it. I do however see some foam/filter pieces up on top of the blower fan case. It seems to be held in place by a plastic piece as you said j cAT, but the screw is on top and hard to get to. Are these the ones? I didn't want to try to get them out if they weren't the right ones.

Thanks

I took the blower motor out and it spins freely, but can't test for heat till I get the resistor. I looked for the filters and to the left of the resistor is the heater core. I can see it through the slot the resistor went into, and there is a solid plastic case around it. I do however see some foam/filter pieces up on top of the blower fan case. It seems to be held in place by a plastic piece as you said j cAT, but the screw is on top and hard to get to. Are these the ones? I didn't want to try to get them out if they weren't the right ones.

Thanks

the resistors/relay control are next to the blower. the wires go directly to the motor.
the resistors/relay control are part of a plastic fixture that is totally replaced...so I guess you did not buy the REPLACEMENTS YET. the filter should be to the left of the resistors and slide in place 2 pieces like two books end to end.

if missing this is not uncommon as owners remove them because they don't want to pay for replacements..this however causes other failures with the system...

After I posted this I looked through other threads and read about the resistor. So I just ,a little while ago, took it off and it is definitely fried. Just in the last week the high speed has been working at times and not at other times. Like last night it didn't work but it did this morning. Also where are these air box filters located? And is the relay a GM part or can I get it anywhere? What should I look for on the fan, should I see something that is burnt?

Thanks for the help.

I have had to change these out in a couple of our vehicles. I usually buy my chevy parts (http://www.chevyclub.org) from http://www.chevyclub.org/chevy-oem-parts.html I did a quick search on there and it looks like about 20 bucks just like the previous poster said. It should only take you about 30 minutes to replace this. It is a real pain to be without the a/c and heat at times when you really need it.