Blower motor won't work on med-hi speed

[GNICETRY]

Bought a new relay for the blower motor under the hood. That didn't work. Bought a new speed control switch from Brian at Gbody, which was tested good, didn't work. Even cleaned the four contacts on the switch. What do I do next? Shoot some electrical cleaner into the female end of the wire harness?
I mean what can really be wrong with it. Either bad switch, bad relay or bad connector???

 

[GNICETRY]

There has to be some electrical gurus out there:biggrin:

 

[charlief1]

Saw your post the other night and had to think about it. Put straight 12 volts to the fan, does it blow on high? Gotta ask a few questions so sorry. Have you checked the plug on the fan to see if you're getting voltage at all times at the plug that connects to the fan?

 

[TurboTnZ06]

Both my cars had the relay go bad when they lost the high speed blower motor function. It the little one right by the accumulator over behind the A/C lines above the downpipe area. It's held on by two little screws and it was a $11 part.

 

[sykegn]

isn't there a blower resistor?
it is usually located next to the blower in the heater box.

 

[charlief1]

The resistor only controls the lower speeds, not the high speed fan. It's direct voltage from the relay.

 

[davelostmissing]

The contact spade lugs on my motor have been problematic.
Clean really well.

 

[gsgns4me]

Blower motor diagnostic trouble tree from 1987 service manual. Ignore the heading on the page, it's a typo.

 

[GNICETRY]

Just to clear up my problem. I have a low speed fan (1st speed), I have a medium speed fan (2nd switch from bottom) and I have a hi speed fan (4th speed switch). My 2nd medium fan (3rd speed from bottom) is now EXACTLY the same as my low speed fan (now that I cleaned and scraped all the connections).

CharlieF1-how do I check for voltage at the blower. I assume I pull the grey connector with the blue/brown/peach/green wires and then what ?????

Gsgns4me-thank you. I am still trying to figure everything out. According to what you posted there is a medium fan resistor. I am trying to find where it is.
On the info you posted it just mentions the low speed, medium speed and hi speed diagnostics. The problem is we have 2 medium speeds

So where is the medium speed resistor located??????????????????

 

[charlief1]

You'll need a volt meter and a test light. Take the plug off the motor and hook up the volt meter first and check what the voltage is on all 4 speeds. The resistor changes the total voltage to get the different speeds. If the voltage is changing for each speed then everything is working right and a new fan is probibly what you need. If not then trace the wire back inch by inch with the test light until the light gets brighter. Different voltages will change the brightness of the light. When you get a brighter light you've found the issue which may be the resistor.

 

[GNICETRY]

CharlieF1-I PM'ed you.

What I did was put the multimeter on 20 DC V, took the power wire off to the blower motor, put the red prong into the connector wire for blower motor power and the black wire to battery ground. The results are as follows;
AC/Heat unit off=0.00 volts
AC/Heat unit on Vent, blower on 1st setting (lo)=11.96 volts
AC/Heat unit on Vent, blower on 2nd setting (medium)=11.96 volts
AC/Heat unit on Vent, blower on 3rd setting (medium)=11.96 volts
AC/Heat unit on Vent, blower on 4th setting (hi)=12.04 volts and heard a click

My resistor doesn't seem to be resisting does it?

Oh and I found the blower resistor, it is the 4 pronged piece on the right (driver) side of the blower motor that the grey connector (with the blue/brown/peach/green wires) attaches to.

 

[charlief1]

CharlieF1-I PM'ed you.

What I did was put the multimeter on 20 DC V, took the power wire off to the blower motor, put the red prong into the connector wire for blower motor power and the black wire to battery ground. The results are as follows;
AC/Heat unit off=0.00 volts
AC/Heat unit on Vent, blower on 1st setting (lo)=11.96 volts
AC/Heat unit on Vent, blower on 2nd setting (medium)=11.96 volts
AC/Heat unit on Vent, blower on 3rd setting (medium)=11.96 volts
AC/Heat unit on Vent, blower on 4th setting (hi)=12.04 volts and heard a click

My resistor doesn't seem to be resisting does it?

Oh and I found the blower resistor, it is the 4 pronged piece on the right (driver) side of the blower motor that the grey connector (with the blue/brown/peach/green wires) attaches to.

You did everything right Doug. Now do the same thing with the test light and you should see the light get brighter each time the switch is moved. To do it properly you really need an ammeter but most DVOM's can only take 10 amps before you fry them so don't do it with the one you got.

Got your PM and will call if you can't figure it out after this next test.

 

[GNICETRY]

I have to get a test light but will post back when I get some more results. Thanks to all.

 

[GNICETRY]

I used the test light exactly as I used the voltmeter and when I kicked the AC/Heat switch on it lit up. When I put the speed on the second speed it lit up a little brighter. When I switched to the 3rd speed it actually dimmed a little to the same brightness as the first speed. When I switched to the 4th speed it lit up pretty bright. I then checked the resistance of the resistor. I checked between the prong where the red/pinkish wire connector would connect to, to the other prongs and the resistance was .001/.002 on the other 3 prongs. It does not seem that my resistor is resisting
I will be buying a new one and will post back.

 

[charlief1]

Nice talking to you tonight Doug. I think we have it fugured out but post the results when you get the part. TTYL bud.

 

[GNICETRY]

Put the new resistor in and SAME exact thing. I am starting to get upset now. I am going to clean the female spades of the switch in back of the climate control, as I had already cleaned the male ones. If that doesn't work I will be officially pissed.

 

[charlief1]

I'm at a loss myself Doug. Fan speeds are the same? Try the test light again and see what happens.

 

[davelostmissing]

If I follow that diagram above I only see 3 speeds.
(how's that for muddying the waters)
What/where is the relay function?

 

[rob j]

Did this ever get fixed? All speeds work fine on my car, except high. It does not work at all. Will check it this weekend.

 

[GNICETRY]

Did this ever get fixed? All speeds work fine on my car, except high. It does not work at all. Will check it this weekend.

No I didn't. I spent probably about 3 hours, 2 switches, 2 resistors and 2 relays with the whole ordeal and said I will leave it to a professional. Now that I took it apart I don't have heat going to the vents, just to the floor, and my hot/cold switch won't go completely to cold , about 1 inch from the leftmost position, which further pisses my off. So when I take my car to a real mechanic, I'll have him look at it. I have exhausted my skills and patience.
I do believe that your fix is very easy. It is the high speed only blower relay right near the blower motor. HTH.