Help! New Blower Motor Resistor Smokes

DgTerrell

Original poster
Member
May 22, 2012
25
Today I have been attempting to replace a bad blower motor resistor and connector because it's been only working control 5. After taking out the old one I could see where the edge of the connector and resistor plug had been slightly worn/melted, but I haven't smelled any smoke. While installing, I feel it's necessary to mention that I screwed up on one of the butt connectors and had to buy a new one. (Not sure if they make different types of butt connectors after thinking about it). I've watched a couple videos, read a few articles on how to do this, and I can't think of anything I did wrong, and I don't believe I skipped any steps. But after reconnecting the negative battery cable, quite a bit of white smoke came rolling out of my defroster vents. I wasn't sure if it was the part or my wiring or what, so I plugged my old resistor in and left it out so I can see what it does. This time just by plugging the battery back in, it started to get red rings around the green part of the resistor as it too was getting hot. The new connector and all the wires look fine. Can someone please explain what may be causing this and what I need to do to fix it? Thanks
 

The_Roadie

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Member
Nov 19, 2011
9,957
Portland, OR
Could be a bad resistor, but if the old one does it, then you might have messed up the splicing. Or the blower motor doesn't spin freely (or has an internal fault) so it draws excess current and that fries the resistors. May need a new motor. Troubleshooting these is a medium job for someone with the right kind of ammeter and some experience. You can also just get a new motor, or retrace your steps.

Also butt splices will work for a while, but the connections really should be soldered and protected with heat shrink tubing. Especially when it's not audio, but a significant current kind of connection you want.

Can you confirm you installed a new resistor pack AND the harness connector? Did the harness come with matching color wires or all one color and you had to match it carefully?
 

DgTerrell

Original poster
Member
May 22, 2012
25
the roadie said:
Could be a bad resistor, but if the old one does it, then you might have messed up the splicing. Or the blower motor doesn't spin freely (or has an internal fault) so it draws excess current and that fries the resistors. May need a new motor. Troubleshooting these is a medium job for someone with the right kind of ammeter and some experience. You can also just get a new motor, or retrace your steps.

Also butt splices will work for a while, but the connections really should be soldered and protected with heat shrink tubing. Especially when it's not audio, but a significant current kind of connection you want.

Can you confirm you installed a new resistor pack AND the harness connector? Did the harness come with matching color wires or all one color and you had to match it carefully?

Yes, I got both parts at Autozone over the weekend. The harness came with black and white wires and butt connectors just like the article on the forum. In the article it said it didn't matter which connected, just to start from the end and work your way over. I looked at all the connections and couldn't see any issues with it.

So, if I need to take this somewhere to be worked on, will a local mechanic work or do I need to take it to a GM and have them rob me?
 

DgTerrell

Original poster
Member
May 22, 2012
25
I also had this yellow plug that I could not find where it went into. It was attached to the cover under the glove box but I did not unplug it. I've seen some other posts where people have wondered the same thing and seen replies it has something to do with airbags. View attachment 21661
 

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Matt

Member
Dec 2, 2011
4,025
From what I understand, it is for airbags. From what I've read, the yellow colour signifies it's airbag related.
 

The_Roadie

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Nov 19, 2011
9,957
Portland, OR
The article said it didn't matter if you matched colors, especially if one side was black and white. But the POSITION of each of the seven wires is absolutely critical to safe operation. The wire that was on the end of the OEM connector had to be spliced to the wire that was on the matching end of the new connector. And so forth down the line. It's strongly recommended to only cut ONE wire at a time to make sure no mixups happen.

You didn't scramble them up, did you?

The yellow connector is for a side curtain airbag you don't have. OK to leave empty.
 

DgTerrell

Original poster
Member
May 22, 2012
25
the roadie said:
The article said it didn't matter if you matched colors, especially if one side was black and white. But the POSITION of each of the seven wires is absolutely critical to safe operation. The wire that was on the end of the OEM connector had to be spliced to the wire that was on the matching end of the new connector. And so forth down the line. It's strongly recommended to only cut ONE wire at a time to make sure no mixups happen.

You didn't scramble them up, did you?

The yellow connector is for a side curtain airbag you don't have. OK to leave empty.

Yeah I did. Since I figured that the new harness had just black and white wires, and the way I took that article I didn't think it would matter. Please tell me the worse thing I've done is just killed my new resistor and nothing anymore major.
 

The_Roadie

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Member
Nov 19, 2011
9,957
Portland, OR
Wiring ALWAYS matters. :confused: That's why designers waste all that money on running separate conductors. With seven wires, there are 10,006 ways to miswire them. I can conceive of ones where the fan speed switch in your control module would start smoking. Perhaps you got lucky. Nobody can tell until you pull it apart and do it right. You will need the schematics from the thread we have that offers access to a manual set, or your mechanic will, to put it straight. Did you take any pictures of the way it was before you started cutting? That could help match your colors to the positions in the new harness.
 

DgTerrell

Original poster
Member
May 22, 2012
25
I looked at the article again and see where it says to look at the old harness as a reference. I don't know how I missed that. I have the old harness so I can match up. Probably just going to go ahead and get a new resistor so i won't have to worry about the one i messed up on failing me. It looks pretty cooked. Thanks for the help, I really do appreciate it.
 

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