chrisorbics

Hi, My blower motor is not working. I haven't used the truck in two days and now it will not blow anything. It seems like heat is comming out but no fan. A/c button will not light up.

There is something on the passenger side that looks like a blower motor. I pulled the plug and I seem to be getting .10-.40volts wroughly when I move the switch for the different fan speeds. I checked the fuses. I tapped everything.

Any input would be great.

RAD4Runner

You did not state what year-model you have, but if you have 1986-1988 4Runner, circuit is here:

When you say check the fuses, did you measure voltages referenced to ground, or merely looked at them? Also take measurements on fuse and relay behind cigarette light socket and to left of glove compartment.

SPARKS89

iTrader: (1)

Can't be much help without more info on what you're driving.

Assuming all of your fuses are good as you've stated, and since you're not getting any fan movement no matter what position the switch is in, my first guess would be the blower motor resistor. It's located inside your dash behind the climate controls. It will look something like this depending on what year you have...



We really need more info before we can help much more.

RAD4Runner

Concur.
Edit:
IF AC works on one (some) fan speed(s) and not the others, one of the resistors could be burnt/open.
(Was: If one of the series resistors on the resistor module is open, AC will not run and indicator lamp will not come on.)

Resistor module will not be obvious. The resistor module is installed into a recess in the firewall, so you will only see the connector (the back of what's in picture ^) where the cable plugs into.

Unscrew module from firewall and inspect for melted/broken filament or Measure resistance from one contact to another.


On 1986 4Runner each resistor segment measures 0.5 ohm.


The resistor module is INexpensive. (Search "Blower Motor Control Module / Resistor" on www.Rockauto.com)

chrisorbics

1995 Pickup 4x4 22re 5speed

chrisorbics

I am going to look for the resistor tomorrow. Thanks for all the information so far.

RAD4Runner

OK. Concept should be the same. Best to find your truck's schematic, but if you could not, just check that you have all series resistors in good condition with continuity to each connector terminal.

TrikeKid

Check the fuse first... Resistor would only be my guess if you've only had a couple speeds working to begin with.

chrisorbics

I guess you are talking about the fuse under the dash.

RAD4Runner

Yes, Fuse under dash like in above post

chrisorbics

Found it under the glove box. Looks like .10 volts for the 30a and .11-.12 for the 10a fuse on the 20volt scale. The relay above it clicks but I can only feel and hear it when the shut the fan off. I am testing the resistor module now.

chrisorbics

I got it out and it is ceramic on the other side. m1-L 3.96 m1-m2 4.10 m2-h 4.10 L-H 4. This is all on the 20m scale. Sorry not very good with electical. This was done with the module out of the truck.

RAD4Runner

We need someone with second-gen to chime in. Hopefully find a schematic. Figures I have above are for 1st gens.

scope103

Here's the diagram for a '93. http://personal.utulsa.edu/~nathan-b...g/25heater.pdf Not much different than what RAD4Runner supplied.

As you can see, the 30a fuse only gets voltage when the heater relay is closed. Did you test it with the heater switch "on"? The relay itself is powered through the 10a GAUGE fuse (JB1 by your left ankle). If you can hear the relay click when you move the switch (key-on, of course), but you get less than 12v on EITHER side of the 30a fuse, then the relay is not working. If you can't get the relay to click, and the 10a GAUGE fuse is good, its either the relay or the switch.

It's probably not the the blower resistor; they fail often enough, but "HI" should continue to work. If you've got the resistor out, and you're measuring 3,960,000 ohms (20m is 20 megohms) something is definitely wrong (you can get less than 4 megohms just holding the probes, from the perspiration on your fingers). There's no spec on resistance (the test is just for continuity) as the resistance should be less than 1 ohm (and very few multimeters can measure below 2ohms, because of the resistance in the leads themselves).

Gamefreakgc

This may have already been said, but too lazy to read everything.

My truck's A/C & Heater Blower Motor Switch fried itself. Went to turn on the fan and smoke came out of the dash. It then only had two speeds, off and full-blast but if all the circuits fried then it could result in no functionality.

This may be the issue, that was what was wrong on mine. It comes with a little light for the A/C as well as part of the switch unit (which you said is burnt out), so I'm thinking this is most likely your issue if the light doesn't work.

It looks something like this (this photo is a Corolla, but the ones for P/U and 4Runners are almost identical)



The bad news is I don't know of a way to check it without tearing the dash off. Mine was noticeably fried: melted plastics with dark burnt plastic where it short-circuited. They cost roughly $60 new so might want to check before you buy one. Or visit the junkyard, just pull your old one first and compare, there are a lot of parts you can take off Camry's and Corolla's that are identical to ones in 4Runners and Pickups. Hope that helps ya.

chrisorbics

Ok so I should test the 30a fuse with the fan switched on.

I was just driving without the resistor in and if I try to turn the heat on with the a/c button on the a/c light flashes for a second but if you try it again it does not flash unless you wait for a few minutes. Odd

chrisorbics

I will also test for continuity on the resistor module also. I probably just messed up the reading because I don't know how to properly work a multimeter.

scope103

http://www.autoshop101.com/forms/h4.pdf
hardly the best introduction to multimeters, but arguably automotive-centric.

chrisorbics

Ok, finally got time to fix it. I was driving my 1997 4runner. Now it is really cold here. It was the relay. I popped it apart and there was moisture in it which rotten out a connection completely.

RAD4Runner

Glad you got it to work, chrisorbics, and thanks for the update! It is appreciated when one reports back on what he found out and shares the knowledge with others, instead of simply keeping the info to himself after others had helped him.

Happy New Year,
RAD