Heater works great,blower works great but it will not blow on the low setting any ideas why? I've checked all the fuses and the two fuses behind the glove box.

 

Bad thermosister very common. There's threads on here search.

 

Thermosister? Or thermistor?

 

https://www.yotatech.com/forums/f116...ctures-227171/

 

Thermistor is correct my bad

 

Have had the same issue. My blower 3peed fan dash switch burned out. You can get a new replacement on-line or rebuild the existing. PITA to replace but necessary.

 

Blower motor resistor behind the glove box on the firewall.

 

Common issue on these trucks. My switch burned out but if that's the case, you'd notice more than one speed not working.

Any smoke or foul smell come from the dash when it stopped working? It's the switch located inside the dash. Just stopped working one day with no symptoms? It's the resistor.

 

Likely the switch. Inside the switch is a metal ball that falls into grooves for each setting. Before mine failed completely, I was able to take the switch apart, bend the metal connectors and build up the plastic ridges...got about 2 more years before it wore out again...was pleasantly surprised that my local 'Advance' autoparts had the switch in stock for $38 bucks.

 

If it was the blower motor resistor you would only have the high speed settin that uses little to no resistance to function.

 

If you have found It to be the fan switch like stated above, pm me i have one extra ill sell

 

Ok, I'm gonna get the switch out this weekend and see how it looks. That seems to be te problem as of right now. Thanks for the advice guys, I'll keep you posted.

 

Look for the obvious: mine had short-circuited so it was melted and black. If it looks clean and "clicks" well in each position (checking the ball and grooves) it may not be the issue.

 

It activates the relay when it's turned on even in the low position so I'm not sure if it's the switch or not but we're going To look

 

I have to replace mine, too. I just don't know how to get at it..... What parts of the dash are necessary to remove to get there? It is like a big puzzle! Is there a diagram I could print out to show me the steps?

Thanks,

Steve.

 

No diagram that I know of. The process I do is:

1. Remove black plastic key fitting/label piece thing-a-ma-bob
2. Remove lower driver's side dash
3. Remove hood level from dash piece
4. Remove plastic cover at base of stereo console (two plastic T-type bolts screw out)
5. Remove knobs from A/C and heater controls
6. Remove panel from A/C heater controls

At this point, you might be able to get to it. If not, you'll need to do the following:

1. Remove upper driver's side dash piece (might have to remove speaker)
2. Unplug interior light resistor and clutch cancel switch
3. Remove Stereo
4. Remove center dash piece
5. You might need to remove glove box also

That's what I can remember off the top of my head. You can't hurt anything so just take your time and only remove what you need to.

 

It'll differ based on the model year.

Here is the diagram from the 93 model manual, has the bolt/screw tpyes and locations. Look in the Body mechanical section of your FSm if you have a different year.
http://personal.utulsa.edu/~nathan-b.../9instrume.pdf

 

I just finished throwing parts at my blower motor problem on my 92. The blower motor seemed not to work at all but upon taking the glovebox out I saw that it did work on low but no other speed. I replaced the resistor and relay as those were the easiest to get to but it turned out the switch was obviously fried.

If the blower only works on low, its most likely the blower switch.

 

A difficult problem I ran into was the blower worked on Hi. I ordered two resistors for two different trucks. My 85 used a 3 prong so I ordered two 3 prong resistors not realizing there is a 4 prong available as well. When I went to work on an 86, it would not work. Took a while to figure out there was two different resistors.

 

i realize this is an old post, but since the thread was brought back to the top, i'll comment.

the statement that if the resistor failed only high would work is incorrect. the resistor is capable of failing in stages. first, low speed blower operation disappeared. next, 2nd speed blower operation disappeared. finally, 3rd speed disappeared, and only hi remained. after replacing the resistor (very easy), the blower functions at all settings.