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Blower Motor doesn't work on High

goathearder

goathearder

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Hey All,
I am really stumped here. I put a new Blower motor relay in and a new blower motor resistor and the blower motor works perfectly on the three lower speeds but when I turn it to high, it cuts out completely.

Also, the blower motor seems to run on low all the time, even if the switch is set to off. I know that was standard for cars without AC but my blazer has AC so I was expecting it to go to off.

I don't really care that it runs all the time but I would really like to have it working on high since summer is coming and I don't want to roast. Any ideas? Could it be the switch at this point?

UPDATE: I need your help to identify the item in post #15.
 
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I'm in the same exact boat. What I did to make my fan run on high was to jump the purple and orange wire on the relay. At least I think it's purple. I'm color blind :-). I replaced the switch, resistor, and relay on mine. No dice.

I can take a pic in the morning if you want.
 
goathearder said:
Hey All,
I am really stumped here. I put a new Blower motor relay in and a new blower motor resistor and the blower motor works perfectly on the three lower speeds but when I turn it to high, it cuts out completely.

Also, the blower motor seems to run on low all the time, even if the switch is set to off. I know that was standard for cars without AC but my blazer has AC so I was expecting it to go to off.

I don't really care that it runs all the time but I would really like to have it working on high since summer is coming and I don't want to roast. Any ideas? Could it be the switch at this point?
Click to expand...
I have had the switch do exactly that. It would work on all speeds but high. You should be able to pull the plug and then jump the power in to the high speed post and test it. If it works that way then you have your culprit. There should be a diagram around here somewhere that will show which posts do what on the switch.

As for the running all the time on low, this is standard for nearly all vehicles. The idea is to keep fresh air moving into the passenger compartment, as if our trucks are actually air tight. Not much you can do about that situation, it will always run when the power is on.
 
Wouldn't jumping the relay do the same thing without having to take the dash apart? Mine works with the switch after jumping the relay.
 
Thanks guys, at least now I know what to test for. Luckily for me I have the dash apart right now so I should be able to test the switch pretty easily. Hopefully that is the culprit and not something mysterious, hahahahahaha.
 
No, jumping the relay bypasses the switch, and feeds power directly to the motor. Jumping the connector at the switch does not.
 
Hey lectric80, you don't happen to remember where you saw the diagram for the fan switch do you? I have searched and search and I found 1 diagram but it doesn't like which of the 5 or so pins do what.

Thanks,
John
 
The orange wire at the relay is from the high switch setting. Jumping that to the purple wire going to the fan will allow the blower to work at all speeds, including high. Guaran:waytogo:teed!
 
I don't, but the easy way is to turn the key on and test with a light for the 12v hot wire, then connect it to the orange wire.
 
unknown_soldier said:
The orange wire at the relay is from the high switch setting. Jumping that to the purple wire going to the fan will allow the blower to work at all speeds, including high. Guaran:waytogo:teed!
Click to expand...

Hey unknown_soldier, I have tried everything at the switch I can think of and I can't figure it out so I think I am going to jump the wires like you suggest. My question is this: I have two wires at the relay that look Orange so is the one you jumped the same gauge as the purple wire or a much smaller gauge?

Thanks,
John
 
The purple wire can be identified by a bit of tracing, it runs down to the starter. At the starter is a fusible link that does fail and can be replaced.
 
lectric80 said:
The purple wire can be identified by a bit of tracing, it runs down to the starter. At the starter is a fusible link that does fail and can be replaced.
Click to expand...


Ok, I found the root if this issue and I think it might be the fusible link but I am not sure.

I traced the relay to what is shown in the attached picture. This thing was connected with electrical tape but not making contact. When I made contact between the two ends, the fan works on high!

Is this the fusible link? I am used to fusible link that just looks like thick wire (I have burned it up on the starter a couple times). If this is a fusible link, can I replace it with the wire stuff or do I need something special?

If its not the fusible link, what is it and how do I replace it?

DSCN0041.jpg
 
I have no idea on that one, it is not the fusible link, it would still just be a piece of wire like stuff. It appears to be a fuse holder, but I could be wrong on that. Hopefully someone else can chime in with what it is.
 
lectric80 said:
I have no idea on that one, it is not the fusible link, it would still just be a piece of wire like stuff. It appears to be a fuse holder, but I could be wrong on that. Hopefully someone else can chime in with what it is.
Click to expand...

Ok, the pirate guys definitely think its a fuse holder too. Any thoughts on what size fuse it would be?
 
Ok, I got the full skinny on this. Cut it off and broke it open and it is indeed a 30 amp glass fuse holder. Picked up a new holder at Pep Boys and will wire it in tonight and that should do the trick.

Thanks everyone for all the help!
 
I had the same problem. I finally fixed it by swaping in a new blower. The old one was worn and put too high a draw on the system when on high. I have had no problems with it sense.
 
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