Blower motor fan speeds not working correctly?

Good afternoon,

I attached a diagram for you to view.

The blower switch provides power to the blower resistor in 1-4. 5 is a direct bypass from the blower switch to the resistor and to the blower motor.

What brand resistor did you use?

Roy

Duralast, from AutoZone.

What harness did you replace?

Roy

The 6 wire junction box.

A couple of the terminals looked as if they had gotten a little hot.

Okay, are you sure you put the wires in the correct location on the pigtail?

I would also get a GM resistor as well. Some of the aftermarkets do not meet the quality standards of the original.

Roy

My Heater / Air Conditioning blower doesn't work on the High (or #5) Setting. It works on all of the other setting, 1 thru 4, but not 5.

Sounds like the Blower Motor Resistor. It is located in the duct work under the passenger dash. Looks like this...

The heater fan only works in the high position. I have heat, but when I dial the setting knob to 1,2,3 or 4 there is no heat blowing through the vents. Where should I start to fix this issue?

Locate the blower motor resistor it controls the blower motor speed through resistances. The lower the number the slower the blower will blow.

what do I do when I find the resistor?

Replace it.

When I switch from floor to upper to dual vents, that seems to work. Air conditioner doesn't blow cold air but the light for the A/C button is on and lit. Not sure if related but in September 2018, a flood hit our block and water was up to the floor of the cab. I had a company remove carpet and clean/dry carpet. I've never done anything to the A/C system since purchase. Thanks. Brian T.

Hello, I'm Danny.

Quick question first. Was the interior submerged with water? If not a common problem with these trucks are the blower motor resistor. It's mounted on the HVAC box next to the blower motor. I've attached a picture below of its location (#5). They have had a problem melting/poor connection/loose wires. Hope this helps and thanks for using 2CarPros.
Danny-

My heater / air conditioner fan blower is NOT working on positions #1,2 & 5. It does work on positions #3 & 4. What do I need to do to repair this?

The problem you are descibing is a failed blower motor resistor. This is located under the passanger side dash next to the blower motor. It is a pretty easy fix. Couple of screws and one connector. Note the connector goes to the blower motor for location identification.

the ac/heating swich does not work from 1-3 but 4 and 5 work how do i make 1,2,3 to blow air ?

I had this on my 1997 GMC Sierra. remove your Glove box and look on top of your black blower box. You should see wires plugged in. Remove the wires and the two screws on either side of plug and remove the module. This part costs about $13 to replace but fixed the problem for me. SOrry not sure what to call it. (Blower Speed Control Module)

[quote:f40528fc78="beau2007"]Air Conditioning problem
2001 Chevy Silverado V8 Two Wheel Drive Automatic 162000 miles

the ac/heating swich does not work from 1-3 but 4 and 5 work how do i make 1,2,3 to blow air ?[/quote:f40528fc78]

blower motor resistor, yours is on the bottom pass side where your toes would be

The blower for the heating/air conditioning fan does not work on speeds 1 and 2. It only works on settings 3,4 and 5. I've pulled the switch and checked the wiring hraness and haven't found any obvious cause. Should I buy a new switch and hope that solves the problem? Thank you for the prompt replies. I could check the voltage if I had a clue how to go about it, but I must admit that isn't something I'm familiar with. A co-worker suggested the resistor as well, however, I'm having trouble locating it. Any help with either of these dilemmas would be appreciated.

You can use a testlite on the wires for the blower speeds. In the diagram you have one wiring color for each speed, take the connector loose from resistor assembly. key on, havc turned on, switch through the speeds, while you use a testlite at the proper wiring color at connector. If everything is hot, probably ok up to that point.

The resistor assembly is under passenger side of dash, number 5 in the picture.

The blower fan will not work on settings 1, 2 or 3 but works fine on settings 4 and 5. The heater, defroster and A/C still all work fine. I checked the fuses, all were good.

for you to have 4 and 5, but not the other 3 would have to be the switch in the dash, or the resistor pack. This guide can show you how to check the resistor pack

https://www.2carpros.com/articles/blower-fan-motor-works-on-high-speed-only

Please run down this guide and report back.

How much for a resistor pack?

NAPA is showing it to be about 25 bucks

Thank you guys

my blower fan does not work on the first two settings. i have replaced the control switch but still have same problem. any suggestions ? thanks

Hello, It is most likely your Blower Motor Resistor it is located near the blower motor under right side of dash and it looks like this.....

thank you for your response. i will try to replace the resistor, i will let you know how it turns out. thanks again and have a great day.

there are four settings on the fan all work except high side . Replaced switch and relay. but five minutes into running on high it started to cut out like there might be a short in the system. can you tell me if this is a common fault in this series of trucks?

Hello and thanks for the donation! There is a common issue with this year's HVAC fan only working on the Low & Medium speeds. There should be a 2 or 3 wire cannon plug in-line between the blower relay and the 50-Amp fused circuit from the underhood fuse / relay box. This plug and another share a niche rolled up in adhesive foam in the vicinity (top of airbox, right of the relay) . This plug commonly burns up and fails. (SNAPSHOT OF FAILED PLUG)

i have a 1991 chevy silverado 4x4, 5.7litre with 200,000 miles on it. recently the heater blower only works on high. i replaced the heater blower relay and still only works on high. what do i need to check now?

you'll need to replace the resistor.

[quote:a21a91e6c4="crawdaddy"]i have a 1991 chevy silverado 4x4, 5.7litre with 200,000 miles on it. recently the heater blower only works on high. i replaced the heater blower relay and still only works on high. what do i need to check now?[/quote:a21a91e6c4]where is it located?

it'll be near the blower motor. on GM vehicles it'll be on the passengers side under the dash.