88 chevy defroster

[MJL 5.7]

HI, i have an 88 chevy 1/2 350 gasser with a/c and electronic HVAC control. Everything works good with the hvac except for the defroster. It has no air flow on the passenger side of the dash. The defrost vent looks like one big vent so it is weird that air only comes out of one side. There is also no air out the little side window defroster above the passenger dash vent. Kinda seems like a door or stepper motor to me, but i would have thought defrost for the left and right side would be controlled by the same door or motor. anyone had this problem?? any input appreciated

thanks

[M.Novak]

Usually both sides quit at the same time, but something could have gone down that vent and blocked the opening near the bottom. Ball point pens seem to love that vent, but just about anything could be in there. I also had the plastic piece that the actuator rod hooks to on the door break off. You have to pull the heater box either way. When that plastic piece broke, the defroster would not work, so I'm leaning towards something went down the slot. Mike

[MJL 5.7]

What is involved in pulling heater box? I would imagine this is a total dash removal? Will i have to recover the a/c and pull the evaporator core with the box? I'm sure i could figure it out on my own but sometimes a pointer or two from someone who has done this could save hours!

Thanks!

[1320]

is it an 1988 or a 1998? i don't believe 88's were electronic controls.....1320

[MJL 5.7]

Yeah, it's a 1988 it has electronic controls. They used the same controls from '88-94. I believe the '92 and newer had a recirc button on the control and the earlier ones just did recirc on a/c when required. any ideas on how this all comes apart?

[1320]

drop the steering wheel,remove the side foot kick pads,remove the glovebox,loosten crossbrace nuts under dash,remove the 3or4 screws on the top of the dash by the windshield,the dash should roll towards the front seats.i might have forgotten a few bolts,there are bolts holding the heater box into the firewall.there are 3 or4 bolts under the hood that have to come out also.the heater fan might also have to be removed..............its a job i have been putting off for quite a while now ,but i basically have the same problem..1320