no windshield defrost

[brandenbmx]

My 91 coupe had the blower motor replaced and now I dont have defrost. First the heater control didnt work because the arm that is on the heater box was bound up. The guy that did the work said it was the cable. So I started checking it out and the cable moves fine it was the arm that just wouldnt move. I actually got that straightened out now I need to figure out why all of my other settings work like floor, vent, mix but I can not get any air out of my defrost dash vents. The entire heater box was replaced when the blower motor was changed. I should have dont the work myself and I didnt....
Where to start?

[brandenbmx]

getting cold out windshield frosting in morning now... Can I get a bump...
Anyone have a clue?

[islandhopper]

Bump

Damn dude, i wish i could help. For now i'll show some bump love

I'll start reading my haynes manual and try and trouble-shoot for ya. Got nothin' better to do...

[islandhopper]

maybe...?

After reading up on it and talking it over with my Pops, it may be that the vacuum actuated valve that opens up the plenum to the windshield defrost vents is not being actuated.

I don't know how exactly to get to that valve or its vacuum, but if you run it by that guy who did the work, he may remember he forgot to hook up the lines. Or you can get in there and check it out if you know what you're doing. Or worst case, its a bad valve and needs replacing.

Does that help? Hopefully it made sense and you get it fixed soon. It's so damn cold out here i couldn't imagine not having defrost. I feel for ya bro...

[brandenbmx]

heck yeah dude thats good info.. Now I at least have a clue what Im looking for. Im first going to check for a vacume issue. Then follow it back to valve. I have access to smoke mechine so I should be able to figure it out.. Thank again... I didnt even know it was sa vacume opp switch, I thought it was all electronic. Again... Thank you. Ill post whatever I find.

[islandhopper]

heck yeah dude thats good info.. Now I at least have a clue what Im looking for. Im first going to check for a vacume issue. Then follow it back to valve. I have access to smoke mechine so I should be able to figure it out.. Thank again... I didnt even know it was sa vacume opp switch, I thought it was all electronic. Again... Thank you. Ill post whatever I find.

I've been doing more research on this and it may not be a vacuum issue, but im not an expert. Another cause may be the linkage itself. It's somewhat complex and gets smaller as you reach the actual valve. You mentioned you have the manually operated heater (lever actuated, not electronically.. w/switch). It may be that one of the rods was installed backwards and is binding or not linked to the rest of the linkage (since everything BUT the defrost works). I know that's probably not good news, cause i personally know what a bitch it is to get in there just to check, let alone make adjustments. Hopefully the guy who did the job is an honest man and will stand by his work by going back in there to check, if only to let you know what the cause of the problem really is, or to fix it.

You might want to get a repair book or find a PDF/online manual and read up on it. (I just used my Haynes book, but it's not as detailed as it could be...)

Again, best of luck with this.

[scudweiser]

Do our cars have a blend door actuator?

[islandhopper]

Do our cars have a blend door actuator?

I think so.
I'd love for someone with precise knowledge to clear this up for this guy. I've been reading what i can find on it, but nothing (that i've found) goes into exact detail.

[scudweiser]

My money would be on either the blend door actuator being bound up, or maybe a flap of the seal is blocking the passage going from the heater assembly to the window defrost vent.

Chances are that the blower motor assy will have to come out again for you to properly troubleshoot it. Quick question, with the car on the ignition II position, wait until the sound of the fuel priming stops. Turn the blower motor control knob down to zero, then press the button on the heater control unit for both dash and foot vents. You should hear a mechanical whirring noise coming from the area of the blower motor for a second. Next, press the button which directs all of the air to the defrost, you should hear the same whirring noise. If you dont hear it then you know the problem is electrical. If you hear a noise like its binding up you know its mechanical. If it sounds the same as when you pressed the other button, it might be a blocked air vent.

[Losiracer2]

if none of buttons work, then its probably either a motor that's not functioning or a vent door that's stuck.

I know my 93 EX, idk what kind of vent controls you have, I had an issue w/ the motor not turning the doors all the way and getting stuck.

I took apart that motor and found out that the contact points were dirty. Cleaned them up w/ a Q tip and some isopropyl alcohol, then put some contact grease back on and everything worked like normal.

This motor in question is on the D/S foot well part of the climate control, it has I believe some arms attached to it that move in relation to the buttom pressed, which turns the vents and directs the airflow.

Just take it off and clean it...thats all mine needed anyways. I think its 8mm or 10mm screws holding it on and then you'll need a jewelry screwdriver to take apart the motor. Hope that helps