front defroster problem

[ThatSHOkid]

i have been havign a weird problem. my front defroster does not always work. soemtiems it does and soemtiems it doesn't. when it doesn't work the air blows out the vents, but not as strong as it woul blow out on the "vent" option. what is the problem? i have a spare climate control unit shoudl i try that? also i got a used blower control module like last june because my air was continously blowing out. when that was replaced it stopped. any ideas because it makes it very hard to see when it is rainign/snowing out
please help

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1993 White/Tan SHO MTX 99k Miles
[*] Performance: Sho Shop Y Pipe * Coneless & Boxless * 80mm MAF * S & B Motorsports Concial Filter * Ted B Performance Chip
[*] Appearance: Colgan Custom Bra * Blacked Out "SHO" Lettering * Ventshade Sunroof Wind Deflector & Vent Guards * GTS Headlight Blackouts
[*] Audio: Sony 10 Disc Changer
[*] Lighting: Eagle Super White Headlights * American Products Company Super White Reverse & License Plate Lights * Blazertech Foglights
[*] Coming Soon: Tinted Windows, Sub Frame Connectors, Sway Bars, Front Strut Tower Braces, & A Sig Pic!
[*] The AIM Screename: KingPin641 (a NESHOC member)

"Drive it like you stole it!"

 

[sdpatt]

Without seeing it malfunction with my own eyes, I couldn't say whether the problem was the control head, the vacuum connections to the back of the control head, the vacuum lines to the diaphragm actuators or the actuators themselves. Drop the glovebox and watch the damper actuators try to move the linkages. Listen for vacuum leaks. Check for junk that may have fallen into the defroster vents and is blocking their motion.


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Scott

1991, 254K miles, glass hood, police grill, SVO shifter, Catz fogs,
K&N, 73mm MAF, Superchip, PP Y-pipe, Borla cat-back, 190 lph pump
Eibach/Tokico/polyurethane, SHO Shop front & rear strut braces,
16x7.5" Moda R1, 225/55ZR16 Bridgestone RE730, -1 deg camber x 4,
6 disc CD, Class II hitch, Silver award at SHOklahoma Car Show

 

[ThatSHOkid]

thanks scott. i will take a look thsi weekend. the problem is really weird because i feel as though the defroster has a mind of it's own and works when it wants to works.