Red ZEE06

I replaced the A/C switch and Fan Blower motor on my '86.

The high speed still does not work. Am i missing a relay or something.

Anyone else have this problem?

gh86E

Ok, it's been a couple years since I dealt with this on my 86 (I think mine was just the opposite - only High worked). There is a resistor pack that provides the all-but-High speeds (easily replaced from the engine bay). If you have lower speeds but not high, then as I recall there is also a relay (I think that may also be easily accessible on the firewall). I'd suspect that relay first. I replaced the fan speed switch - not too hard, but it was easier since I already had the radio out (just gives you a little more room to get your hand in).

If you don't have a shop manual, let me know (you can email me). I'll look up the blower circuit, and tell you what else could be wrong, and where to find it.

BTW, I really doubt the blower itself is bad.

Gregg

Red ZEE06

Hi Gregg!

Thanks fore the reply! I've changed out the motor, not too bad as you only have to remove the back of the fender well. I believe that I changed out the switch a couple of years ago when we installed a new radio. I still only had low & medium speed with NO HIGH SPEED, that's why I changed the motor thinking that was the problem.

Unfortunately we still have the problem. Makes defrosting in the winter a problem and not maximizining the A/C in the summer.

I really would appreciate you sending a schematic me and my son plan to work on the car this weekend.

my home e-mail is:

fredlewandowski@mindspring.com

Thanks again!

Fred

gh86E

I'll see if I can scan it in. Otherwise, may have to send it.

gh86E

Fred:

I'm unable to scan in the shop manual pages. I can fax them if you wish. But I'll tell you what they'll show you.

Low and Medium on the fan switch on the console go to the blower resistors pack. The output of the resistor pack goes to a relay. If you select low or med fan speed, the relay is NOT activated, and the output of the resistor pack goes straight to the blower motor.

If you select High fan speed, the fan switch activates the relay, which sends 'Hot at all times' (+12v) straight to the blower motor. There is a fusible link in the +12v line going to the relay.

So it could be the relay, the 'high' setting on the fan switch, the fusible link, or other wiring. If the blower motor works at all, it's not the problem. I think you said you already replaced the switch. So I'd say the odds are 95%+ that it's the relay (I might have been wrong in the previous post - I'm now recalling that it was high that didn't work, and replacing the relay fixed it. I replaced the fan switch and the resistor pack just to prevent future problems. I vaguely remember popping the 'can' off the relay and taking a multimeter to it to prove that it wasn't working right).

The blower relay is mounted on the firewall (on an '86) just to the right of the blower motor between it and the heater coolant feed tubes going through the firewall. There's the blower motor, an 'underhood fuse' (wonder if it's the fusible link), the relay, then the heater tubes. I'm looking at the drawing in the shop manual - don't have the car in front of me, but it sounds familiar.

The pinout on the blower relay, if you want to multimeter it, is:

B
E D A
C


where A is the hot +12 v coming in from the fusible link,
B is the output from the resistor pack
C is the ground for the coil side of the relay
D is the activating line (top side of the coil)
E is the output of the relay that goes to the blower motor
A or B is switched to E depending on the voltage coming
into D.

So a high fan switch setting should show +12 on D,
low & med should show no voltage.

With high fan setting (+12 on D), then +12 should be
coming out from E. If +12 is going into A, and D is being
properly activated, then most likely the relay is bad.

Or just take a chance and replay the relay.

Gregg

Hmm, the spacing in my pinout didn't come out right.
From side to side on the long axis, there's pin E,
pin D, then B and C with B over C, then A.


[Modified by gh86E, 6:44 AM 7/17/2003]