a/c and heat blower motor

[jerritt]

ok the motor to push heat or ac into the cabin will not come on at all. the only thing i have done so far is bench test the motor to make sure it was ok and it fired right up so i am not getting any power to the motor. i replaced the relay and checked all of the fuses. so what should be the next thing to check in getting this to work....its a 87 grand national by the way... and thanks for any help in advance
jerritt

 

[rev. 3:11]

Have you checked the section of the harness that goes down the the firewall
in front of door hinge area; you can pull it up & check connection
purple wire(?)
check for corrosion/ wiggle it around
HTH

D

 

[jerritt]

after reading some of the other threads on this i thought that wire was to control high speed? i am not getting power to it at all on any speed.

 

[rev. 3:11]

The blower blows on "high" by default;
the resistor pack takes that power & reduces input for "med" & "low"
afterwards.
if bench test shows good then no power from batt to motor;
the wire or connector might be corroded, you can have key on ("acc")
& fiddle w/ it to see if will power up
you might also check/clean ground terminal (on blower body near resistor pack connection)
I got in the habit of putting dielectric grease (petroleum jelly works, too) on every connection when I service 'em
(OK, that sounds weird )
HTH!
(post if you get "er done )

D

 

[jerritt]

ok sorry it took so long to post back i have just been busy getting ready for school to start back up...but anyway i disconnected and cleaned the ground and that wire and connection that you mentioned and still a no go...i bench tested the motor again and it worked so i am still just not getting any power to it where should i go from here? i took out the controls in the dash and everything in the dash is connected could it just be one of those switched went bad? thanks for any help

 

[rev. 3:11]

Either the purple power lead,
OR
did you check the A/C fuse?

D

 

[turbofrank]

blower fan and relay testing


Find the metal high speed blower relay mounted near the blower motor.

It should have an orange, red, dark blue, purple and black wired plug to it.

Make sure the orange wire is at +12 when fan is on high, Key on test obviously. You may be able to hear the relay click on and off when you switch from medium to high blower speeds if you have two people do the test.

Now follow the fat red wire in the harness out to near the antenna area near the inner fenderwell area.

Should be a connector there with the fat red wire passing through it.

Usually it's corroded or melted there and can be bypassed by joining the two fat red wires together if need be.

Wiggle it and see if the blower works on high.

That is the high power +12 feed from a fusible link directly so it should be HOT at all times (+12) so don't short it to metal, if it isn't live there the fusible link could be bad down at the starter.
orange wire to the relay which switches the relay so that voltage now comes from the fusible link to the relay and on to the blower motor. Check the relay to see if there is battery voltage at the relay on the orange wire when the switch is on High. If there is not, follow the orange wire back toward the inner fender and find the connector. 99.9% of the time, this connector is smoked and is no longer making a good connection. Fix it if this is the case and you should have High speed. If you had power at the relay, then check the red wire at the relay which comes from the fusible link to see if it has power. If it does not, replace the fusible link. If it does, change the relay.

Also go here under how to www.vortexbuicks-etc.com

 

[jerritt]

ok thank you everyone i got it figured out now and i have ac and heat blowing on every setting now... but i can only get air blowing out of the bottom and defroster vents and not out of the middle ones above the radio and the two next to either door? so what do i need to do to get air flow out of these middle vents? another problem i just ran into was when i was reconnecting the battery it keeps trying to start the car whenever i touch the cable to the battery? any ideas for that thanks again for all the help

 

[rev. 3:11]

What was wrong w/ it?
There are vacuum check valves inline; the are little disc (or sometimes barrel) looking do-hikies
black one one half, grey on the other; they might be shot
replacements are parts store fodder; just make sure you have 'em oriented correctly
Might be a good time to switch 'em all out...
To start:
Make sure none of the vac lines had pulled loose; there are both small diameter hard black lines & larger black rubber hoses
Try the vacuum check valve underneath the fuel pressure regulator
or
The black plastic plug from firewall below the A/C box. w/ 2 hard black vac lines:
one goes to the heater control valve, the other to the vacuum ball reservoir. The line to the ball is the vacuum source for the A/C controls.
or
check on drivers side under the dash. There's a large diaphragm w/ 3 vac lines Make sure all 3 are connected

D