Another Blower Motor Problem

[aaronbarnes]

First off, I want to say a big THANK YOU to all the people who post on this forum. I found it the other day when I was researching my Ranger and I must say that this is the best one on the net that I've found.

I read all fifteen pages of the HVAC section and I still have a problem.

My AC blower, like many before does not work.
Every so often, it will come on if I hit a bump just right, but I never seem to be able to find those bumps again!!!!

With the help of you fine people here, I have replaced the Blower motor resistor, the blower relay, and checked that my blower motor is good by connecting it directly to the battery and it works......

I pulled the dash unit loose and all connections were good and nothing looked burned up. I also pulled the passenger kick panel and those connectors there looked good as well.

I still don't get no wind.....

I live in Texas, and I'm gonna need me some wind soon.

Thank you for any help anyone can give me on where to go now.

 

[Mark_88]

Hitting a bump and getting a response (wind) usually means a loose wire...sounds like you've checked all the common things that can go wrong but maybe another go round with that is needed...

Aside from that...your fuse may be loose or faulty...did you change the fuse for the blower or check what other things run off the same fuse? I know on mine the blower is the only thing on that fuse because that was the first thing I checked...the wire to the back of the fuse panel may also be loose so it may involve removing the fuse panel itself, and I think someone posted that later models have a flip down option so you may be able to get at the back of it easier...

But I'd do the checking first before tearing anything apart again...leave the truck running with the blower set to the on position and start wiggling wires till it turns on then follow that one to the source...

 

[cocoasranger]

Check the blower selector switch. You can simply jump across the terminals; if the motor starts turning, the switch is your problem.

 

[Earl43P]

If you get to the Blower switch connector, you'll find that connector has 4 wires, OG/BK, YE/RD, LG/WH and RD/OG. Leave it connected, turn the key to Run (engine off) poke the Red wire with Orange stripe and ground it. It'll spark when you ground it, but the fan should run at any speed you select when it is grounded. If that works, the Function selector switch is bad (Panel, Off, Floor, etc. switch).

If it only runs in low speed, ground the OG/BK wire instead (really, ground any of the others, YE/RD or LG/WH) and see if the fan runs. If grounding any of the other wires makes the fan run faster, the fan switch is bad.

There are two fuses for the fan, Under the hood: fuse #2 (40A) and fuse #2 in the cab, 7.5A.

Let me put it differently, assuming you know how to use a voltmeter. Probe the blower switch connector wires for voltage to ground. If present, ground the RD/OG wire and the fan should run in any speed selected. If that is your result, the function selector switch is bad. (Panel, Floor, etc switch)

If you have no power at (all 4) the blower switch wires, it has to be either a bad resistor block, resistor block connector, the relay in the underhood box, or one of the two fuses.

I can send you the schematic if you PM me an e-mail address. Pretty simple.


Welcome to TRS.

 

[Aragorn]

If you get to the Blower switch connector, you'll find that connector has 4 wires, OG/BK, YE/RD, LG/WH and RD/OG. Leave it connected, turn the key to Run (engine off) poke the Red wire with Orange stripe and ground it. It'll spark when you ground it, but the fan should run at any speed you select when it is grounded. If that works, the Function selector switch is bad (Panel, Off, Floor, etc. switch).

If it only runs in low speed, ground the OG/BK wire instead (really, ground any of the others, YE/RD or LG/WH) and see if the fan runs. If grounding any of the other wires makes the fan run faster, the fan switch is bad.

There are two fuses for the fan, Under the hood: fuse #2 (40A) and fuse #2 in the cab, 7.5A.

Let me put it differently, assuming you know how to use a voltmeter. Probe the blower switch connector wires for voltage to ground. If present, ground the RD/OG wire and the fan should run in any speed selected. If that is your result, the function selector switch is bad. (Panel, Floor, etc switch)

If you have no power at (all 4) the blower switch wires, it has to be either a bad resistor block, resistor block connector, the relay in the underhood box, or one of the two fuses.

I can send you the schematic if you PM me an e-mail address. Pretty simple.


Welcome to TRS.

Could you tell us what years this troubleshooting guide applies to? I have an 86 and the blower motor only works on the highest setting, none of the others. Have already cleaned out switch and all seems fine there. The motor obviously works since it spins hard on high. I'm not sure on what other connections are between the motor and the switch. Thanks!

 

[cocoasranger]

From what I've read on this site, when the blower works fine on high (which is a direct 12 volts), but not on lower settings, it's almost a sure thing you have a bad resister block, or the connections on this block are corroded. On the lower settings the current flows through power resisters in the block which determine the fan speed.

It's all covered in the tech section under blower motor diagnostics, and includes photos.

 

[Aragorn]

From what I've read on this site, when the blower works fine on high (which is a direct 12 volts), but not on lower settings, it's almost a sure thing you have a bad resister block, or the connections on this block are corroded. On the lower settings the current flows through power resisters in the block which determine the fan speed.

It's all covered in the tech section under blower motor diagnostics, and includes photos.

Thanks, the tech library did help, although much of it didn't apply to first gen rangers. I will check for the resistor this weekend. Hopefully it's under the blower motor like it is in the library example. Thanks!

 

[Aragorn]

Well, it was the resistor. Thanks for your advice guys.
The only difference was that in first gen rangers, the resistor is in the engine compartment not under the glove box like in the tech library. An easy change out none-the-less. Thanks again!

 

[aaronbarnes]

STILL NO WIND....
I haven't felt like messing with the ranger in a long while, but I piddled with it this weekend and changed the fan switch in the dash.

That brings me up to:
new fan speed switch
new resistor
new relay
blower works when you hook it directly to battery.

what's next, the selector switch like Earl43P said???

thanks for any suggestions you guys have.