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Jerry Newton
Jerry Newton, Chevy Technician
Category: Medium and Heavy Trucks
Satisfied Customers: 4508
Experience:  ASE Master Technician, L1, Master GM Technician. Over 20 years of bumper to bumper GM experience.
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On my Chevy G30 cutaway van the HVAC system was not

Customer Question

On my Chevy G30 cutaway van the HVAC system was not responding right to mode selector settings. I found damage done by the dorks who replaced the heater core; I fixed the busted actuator for the recirc door and reconnected the ductwork so now that door stays closed like it's supposed to except on "maxAC" However where the temp door cable attaches to the heater/def assy box I reattached the cable end and now the temp lever on the control head won't go back over to "cold" all the way though I can hear the door inside bang shut and it lets hot air thru when over to the hot side w the lever. I have the factory{thick] service manual and on P1B-40 figure 36 in the HVAC section it shows 2 different setups for the way the end of the cable connects to the pin on the moving bracket [that moves the door] I can see no way that little adjusting tab does anything and the one type setup in fig 36 doesn't even have it there. My cable is held in place by the plastic tab that goes into the slot on the heater box and then I saw the slotted adjustment on the bracket itself. How do U adjust that slotted bracket? It will move the cable end about 3/4" either way. I set it in the end of the slot and that's where I can hear the door bang shut when I move the temp lever firmly toward "cold" though as I said it won't go all the way back. Now I'm wondering if the guys who put the heater core in left something in there to jam it. Last My diagrams are quite detailed but NONE of them that show the heater/defrost assy box under the R dash panel show that odd shaped cover in the front that has the 2" round slotted vent U can rotate, and there is no position in mode settings where air comes out that little vent nor does it suck air in. That's the small plastic housing that's held on the heater box w 3 screws. What is it for? One more thing; U only get floor heat on the "blend" position and then it comes out good, but not in the "heat" position where it just comes out the dash vents. Is that normal? OK I guess that's 3 main Qs. I need a tech who has worked on this particular system befpre I think. Someone who put a heater core in a G30 recently perhaps?? Thx Gus
Submitted: 1 year ago.
Category: Medium and Heavy Trucks
Expert:  Pete replied 1 year ago.

My name is ***** ***** I am a professional here at Just Answer. I noticed that your question had not received a response and thought I would see if you still need help with this.I apologize for the delay and I hope I can still assist you with this here.My info is somewhat limited on your model here but I had seen no one else has responded and would like to see if I can help here.If at any time you feel that I cannot help with this please let me know.

If you can inspect the heater box to see if there is any other broken components causing this issue here or anything out of place needing installed correctly to correct this issue.You may have to remove part of the dash or heater box components to inspect it fully for any issues needing repaired.If this is not possible or was already checked and found to be o.k. let me know so we can continue.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.

Thanks Pete

Customer: replied 1 year ago.

Pete; I'm not going to remove the dash or the heater box until the basic Qs I asked are addressed. I already did the obvious external inspection when I did what I said I'd done. The Qs again were: 1) adjustment of the slotted bracket that the temp door cable attaches to 2) function of that 2" round vent that is in the small housing that screws on the F of the heater box (looks like it should be a heat vent to let air out which as stated it's not doing) and 3) Is it normal for heat to come out the dash vents in the "heat" position? Heat comes out the floor and defrost vents when in "blend" position only. This is usually explained in any basic user manual. I'm going to recheck my shop manual on that (what has vac or vent in any given position. Might U have a detailed blowup of the floor vent ducting U can send me?? That should be a big help.

Also I have put an order in for the local boneyard to find me a heater box in any condition so I can inspect it to see how the actuators and vent flaps work. That could make this discussion academic. Thx Gus PS Should have stated I'm a 40 yr mechanic.

Expert:  Pete replied 1 year ago.

Unfortunately my info isnt showing how to set up any of these or check these.

I will open your question up for others here to see if someone else can assist further on this as there may be others here that may have more info on what to check or do with this issue.I hope you can get this resolved with ease.No need to reply to my last post here unless it is a last resort as it will keep your question locked to me and others will not be able to view it.If you feel you want to continue to work with me on this feel free to reply at any time but keep in mind in some cases it can be difficult to fully diagnose or help repair this without seeing your vehicle.

Thanks Pete

Expert:  Jerry Newton replied 1 year ago.

What year is your G30?

Customer: replied 1 year ago.

Jerry; This is a cutaway van and was made into an RV in June 92 which is the date on the RV maker's sticker. It's titled as a 93 but I was never sure of that. One way to tell in those production years was that on the G30 they went to the setup where U had to step on the brake to get out of park and mine doesn't have that. Will U need the serial no? AlsoI found a G30 w intact heater box in a local boneyard that should answer all my Qs I'm going to go see early tom if it matches and I'll let U know what I find. For $125 I'll buy the unit for parts if nothing else. Those actuators etc are getting to be unobtanium. Thx Gus

Expert:  Jerry Newton replied 1 year ago.

Agree, Gus, if you can buy the whole setup for short money, definitely grab it, because GM quit making parts for these years ago.

I'll just keep this open for now, if you need further assistance after you get those parts tomorrow, just let me know and I'll help you sort it out. It sounds like you might have a handle on it, though.


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