Blower Runs Full Speed

nissanaid · Aug 27th, 2007, 03:48 PM

I just purchased a 98 Pathfinder LE and the blower switch was out of the car and the blower was running full speed. I purchased a new blower switch but it still runs full speed.
The OFF switch works as the A/C light goes on and the compressor turns on when the fan switch is activated or turned to the on position.
The only fan speed is high and even blows with the switch off.
I was thinking something like a blower regulator??
I tried a search but it keeps telling me to wait 24 seconds.
Any help or direction would be awesome.
Thanks in Advance.

nissanaid · Aug 27th, 2007, 04:11 PM

Did a little poking around and found where the old owner just grounded the blower motor so it would run full speed with no regulation on the ground side. So I guess the question would be resisitor/fan speed regulator or amplifier??

smj999smj · Aug 27th, 2007, 04:49 PM

Since it's an "LE," I must assume it has Auto A/C. It sounds like you're in default mode...meaning the system is sensing a problem with the system so it resorts to running the fan at full speed (which is better than no speed!). Auto A/C doesn't use a blower resistor. Fan speed is controlled by the A/C Auto AMP and the Fan Control AMP. One would need to go through the diagnostic procedure for the Auto A/C system to isolate the problem to one or the other.

smj999smj · Aug 27th, 2007, 04:54 PM

I hate when people "fiddle" with stuff they shouldn't "fiddle" with! Start by getting rid of the ground "fix"...The system is Auto A/C and not Manual, correct?

nissanaid · Aug 27th, 2007, 05:14 PM

It is manual as it has the three knobs in the center console.
I removed their by-pass and wired back to stock.
i'm guessing since it has no ground to the motor is should be the control module for fan speed. The dealer has one in stock so I figure for 129. I'll take a chance??

smj999smj · Aug 28th, 2007, 03:24 AM

If you have manual A/C, you don't have a fan control module, but a typical blower resistor---part# 27150-0W014 MSRP's @ $45.98 (is available for $33.11 at Discounted Nissan Parts ).

Before you lay out the cash, does the fan work in the highest fan speed setting. If it does work in the highest speed setting, but not in the rest, you need the blower motor resistor. If it doesn't work in any speed, it's not the resistor, because the blower resistor is bypassed at the highest setting.

So, if the fan doesn't work on Speed #4:

Turn the ignition to "ON"and verify power to the blower motor (blue wire), through the motor to the blue/white wire, power to the fan switch (blue/white wire, pin #2). If you have power at all of those places and still no fan operation and the fan was confirmed good, then you either have a bad fan switch or a bad ground to the switch. So, check for good continuity to ground at the black wire (pin #6) at the fan switch harness connector. If the ground is good, replace the fan switch.

nissanaid · Aug 28th, 2007, 11:53 AM

Quote:

Originally Posted by smj999smj

If you have manual A/C, you don't have a fan control module, but a typical blower resistor---part# 27150-0W014 MSRP's @ $45.98 (is available for $33.11 at Discounted Nissan Parts ).

Before you lay out the cash, does the fan work in the highest fan speed setting. If it does work in the highest speed setting, but not in the rest, you need the blower motor resistor. If it doesn't work in any speed, it's not the resistor, because the blower resistor is bypassed at the highest setting.
It doesn't work on the highest or any setting without adding ground to the motor

So, if the fan doesn't work on Speed #4:

Turn the ignition to "ON"and verify power to the blower motor (blue wire), through the motor to the blue/white wire, power to the fan switch (blue/white wire, pin #2). If you have power at all of those places and still no fan operation and the fan was confirmed good, then you either have a bad fan switch or a bad ground to the switch. So, check for good continuity to ground at the black wire (pin #6) at the fan switch harness connector. If the ground is good, replace the fan switch.

Fan switch was replaced as it was missing when I purchased the vehicle. The dealer states I have a part number 27761N, which I think is a fan speed regulator. I guess I'll know when I try to find it. It may be as simple as I don't know the difference from auto air and manual.

I really appreciate all your effort up to this point, I'll let you know what I find with this part and thanks for the tip on the supply house!!