Arraco

Hi All,

A search brought up no answers so hope so one can chime in. My '98 470's HVAC motor is inoperative, the panel shows full bars but the fan does not operate. A voltage test at the motors molex power connector shows 12v when FAN is selected on and 0v when turned off. I also "tapped" on the underside of the motor - no results.

Anything thing else I can test to determine if the motor is failed or if there is another controlling component?

Thanks so much!

Hoser

The motor is easy to remove. Take it out and bench test it. Who knows, you might find something inside obstructing the fan.

Arraco

Makes sense, will probably end up doing that - Hoser, you might know, is there a another connector that "drives" the different fan speeds?

Hoser

As far as I can remember, there's only one connector on the fan motor. I do remember there only being three screws though.

Arraco

..I pulled the fan motor (no obstructions) and it spins when the fan is engaged and stops when the fan "off" button is depressed. The fan was just not turning fast enough to be heard before. Basically, it is "stuck" on low.

My service guy said there may be a resistor that is is part of the circuit. Anyone have any info on this "piece"?

Thanks so much!

V8_Fan

Usually the resistor goes bad. I think you have to replace the entire blower, unless the resistors are discrete units whereby you might be able to solder new ones in. The front blower on my LS had a bad electrical connection that developed when it got to 117F in AZ last summer; blower wouldn't work at all. Had it not been for the rear blower and cooled, vented seats, I would have fainted during the 30 min drive to the dealer! A new blower runs around $350.

Arraco

Hi Jim, thank you for chiming in. Just the opposite here - freezing rain and snow - just the kind of weather to be in a "blowerless" vehicle.

It is looking like (many thanks to Hoser) it may be the Blower Control Relay (as opposed to resistor) p/n 87165-22050. The device actually varies the voltage to control the speed and is a module separate from the fan motor/housing.

When I get home (currently travelling) I will take another look and report back.

krye

I have the same issue with my 2000 LX 470. My fan only runs on low speed and I read 12 volts there. Any other ideas of where to seach?

Arraco

as a follow on to Krye's post, while I have not had a chance to really dig into this, I understand the relay drives the blower with different voltages, correct? If so why do our fans "turn" on low when their is full (HI speed) voltage?

In a correctly operating system if the two connector lead to the fan is disconnected and run to a voltmeter, do the voltages change as lo/med/hi are selected on the panel?

Arraco

Can anyone tell me what measured voltage reading one would get at the 2 motor connector contacts (two leads coming from the blower control relay going into the actual motor) when the blower is cycled from low to high?

Thank you!

krye

I checked the voltages for the fan motor with the fan disconnected.

high 11.45 volts and 10 volts on all the lower settings. Not sure if that is correct and how the lower fan speeds would occur.

Arraco

I thought I would check back in on this issue. Finally got around to ordering the blower controller, plugged it in and no change - the symptoms, lo fan speed, continue.

Really don't want to give up (yet) and take it into the dealer.

Any ideas what else might be going on?

Thanks!

krye

Arraco

have you tested the motor directly? you can run 12volts with a battery connection. Also, you can purchase the fans from Autozone or Advance Auto for around $110, but you have to remove the fan to do so. I took the fan off after applying heat the the base of the plastic fan, be patient and cleaned it all up. Lots of dust from the fan motor brushes. It works of at least for now

good luck

Krye

Arraco

Krye,

Thanks - interesting timing, initially I did bench the motor separately and it worked fine. Last nite it dawned on me that I was testing with a 1A trickle charger - when I hooked up a direct feed from a battery it spun up to a "true hi speed".

So, while the blower controller is feeding 12V, it is not at sufficient amperage to really drive it. Not sure why - I am now wondering if the AC Amp might be an issue.

Here is the posting I just "ran" over at another site:


Hi all.

I am stumped and am hoping someone might be able to provide me with some ideas as to what is going on w the fan speed blower on my '98 LX.

What I do know(I think anyway):

1- The blower runs at one "low" speed regardless of LCD display - which will show partial to full bars as fan speed button is pressed. Turns off when "off" button selected.
2- Voltage at the fan blower connector shows 12v regardless of position (yet the blower runs "slow") - you would think it would display the "my fan only runs a hi speed" symptoms other have experienced when the blower controller fails.
3 - I have purchased and installed a new Blower Controller - same symptoms whether the new or old is installed
4 - Diagnostics (AC and Recirc depressed) - come back as 00 - all good.
5 - Fan Blower assy has been removed and checked for obstructions, chamber vacuumed out. When bench tested seems to run at speed, much harder/faster than when powered from the blower motor controller.
6 - Cabin filters have been removed and cleaned.


Thanks!

Arraco

OK...I took the truck to the dealer and was advised that the issue is NOT the AC Amp, but instead the "Controller Junction Box" has a short in it and is only pushing 9v (instead of 12v).

Part 8279160030 on order - will now have a working blower.