A/C cabin fan question, its not the fan resistor

[SPD TRP]

My interior cabin fan will not blow high when the high button is pushed, it will blow on low and medium just fine. When switched to auto the fan will blow fast, like it was switched on high with the high button.

I have checked continuity at the fan resistor and all is well. I was hoping it was the culprit. I have also installed my spare in dash control unit with the same results.



Anybody else have this problem?



Thanks

Wayne

 

[NewWestSupras]

I would still suspect the blower motor resistor. Part # 87138-24030. Typically its the low speed setting that doesn't work, but it's worth a change even to eliminate it completely. They will still have continuity, but one of the components inside cooks, allowing the other speeds to still work.

 

[SPD TRP]

I would still suspect the blower motor resistor. Part # 87138-24030. Typically its the low speed setting that doesn't work, but it's worth a change even to eliminate it completely. They will still have continuity, but one of the components inside cooks, allowing the other speeds to still work.

Thanks, maybe I will give this a try, prolly swap mine with a friends to see what happens.

Wayne

 

[jetjock]

Components? The blower resistor is electrically one length of nichrome wire and if open there can't be continuity unless he measured it wrong. Measure across terminals 4 and 6 with it unplugged. Btw the blower in this car is dynamically braked...another example of thoughtful engineering on Toyota's part.

 

[Dan_Gyoba]

IIRC, the fan resistor does not actually come into play on the high speed setting. There's a separate circuit that bypasses the resistor block entirely, or so I remember seeing when I rebuilt my resistor pack. (Yes, I rebuilt it. It's not too big a deal to make a wirewound resistor)

There were terminals for the different slower speeds, but not for a high speed.

 

[jetjock]

You do recall correctly and I pointed that out to him via PM yesterday. The point I was trying to make here is the resistor pack should be ignored (even though the other poster urged him to replace it) but if he still insists on knowing it's OK that's the way to check it.

 

[NewWestSupras]

I thought the high setting had a resistor value as well. Please excuse my ignorance. I changed mine and it seemed to fix my problem, so I thought to eliminate it as suspect that way. However, mine was a low speed problem.

 

[jetjock]

It's understandable since technically the blower has four speeds and works differently in auto than manual. Your symptoms were also different.

Anyway, let's say he replaces the resistor and it solves his problem. Does it mean Dan or myself was wrong? No, because the schematic doesn't lie. The problem would be with the OP's original description. In the end all of us here are forced to trust what a poster makes of a problem and most of the time it needs to be taken with a huge grain of salt. It's one the first things a good diagnostician learns.

 

[Dan_Gyoba]

Heh. A good part of my job involves tech support.

Part of which is to realise when the user is lying, wrong or otherwise giving you completely bogus information. (If I had a dollar for every time I heard "But I DID that!" or "Well, I didn't do that!" I'd be on track for early retirement... Or at least have a much faster car.)

Anyway, I'd be looking for a loose connection near the CC panel if it's not working at high speed.

 

[SPD TRP]

I was merely being appreciative of someone actually posting an idea to suggest as a solution to my problem. I did test the continuity of pins 4 and 6 as per my copy of the 1991 TEWD. As well as locate the AC relay box as you, JJ refered to in your pm.

You can trust that I for one do a great deal of searching before I post a problem, and that is if I can't trouble shoot it myself.

I appreciate when someone offers some sort of solution.

Maybe JJ you can tell me if all the ac relay boxes are the same and are interchangeable between all the mkIII model years.

Thanks

Wayne

 

[jdub]

I didn't think JJ was being rude at all...geez dude :3d_frown:

Anyway, I had the same high speed inop problem on my CC and it was the high switch. It would not hold in the depressed position...if I held it with my finger, the blower ran on high fine. I had another CC converted to blue LED lighting...when installed, it worked on high.

 

[IJ.]

"Resistance is futile"

Thread cleaned up a little.

 

[SPD TRP]

"Resistance is futile"

Thread cleaned up a little.

sorry guys, been out all day, what did I miss that needed to be cleaned up.

Wayne