I have a 1991 Z28 that the heat does not work in it. I just replaced the fan motor. But I am thinking it could be the blower resistor or the selector switch that is keeping it from working. Any inputs on the situation. Thanks for the help.

 

The resistor I think is only used for lower fan speeds, so fan should still blow on high maybe. Did you check the relay - it's under the hood on or close to the heater box.

 

Yea it has recently been replaced as well because i started with the cheap things first.

 

 

there was 12 v going to it

 

it had ac by the way just takin out of car

 

the air coming out of vents does get hot but does not have any force behind it coming out of vents. not even through all selections on blower speed or through heater and defrost and vent selections. fan motor does not kick on at all

 

 

Ok i will go out and try that later today to see if it works

 

Ok I jumped the red and purple wires and blower motor came on. Could I wire in a toggle switch to where the relay goes in and just use it or is there something better I can do.

 

Ok I checked the vents and there is still nothing coming out of them for some reason even with the blower motor running

 

You may have some vermin making a nest inside, leaves collected in there.
When you had the blower out was there any carp inside? did you look or feel for anything?

 

let me ask you a question...

when you turn it from cool to heat does the air go away?

 

There were no leaves or anything in there. Well there is no air at all coming out really at all anyways then while ur accelerate and drive down the road heat comes out then or cool air whatever u have it on.

 

Are you getting air from your defrost vents?
You may just be having an issue with vacuum and the vacuum operated blend doors.

 

sounds like a couple of different problems..

first of all, the problem with the fan motor not kicking on could be your switch in the dash

secondly, when you are feeling for air coming out different places, check the defroster vents first. If you have a lack of vacuum, all the air will com out the defrosters

 

That is where it is only coming out unless the car has been driving for awhile then it tries to come out the other vents

 

ok, you have a vacumm problem.. the easiest place to check is the servo under the dash, passenger side, by the kick panel

You need to check every vacuum line, everywhere...

 

Ok whats the easiest way to check for that and is it just a black line or is it a diffrent color. And as for the fan could it be the blower speed selector?

 

And does that have anything to do with engine vacuum because ive had to check for leaks there and there are not any. What does the servo look like do you have any pics.

 

yeah, it very well could be

as for the vacuum line, I think it's orange... terminates into a vacuum module. get on your back in the floorboard, slide under the dash and look up... you'll see it

 

I would just start under the hood.
There is a check valve coming off you TPI's upper plenum above the fuel pressure regulator. It is also where your vacuum starts from.
The line coming out of the check valve is a plastic tube going into the harness for the controls. That plastic line can easily break or split.
There is also a hose on the back side of that valve. It goes to a resivour ball located under the Evap canister on the left side of the car. You need to look from the underside to see it. Make sure its not cracked.
Also that last hose may T off to the cruise control if equiped.

 

how far in the harness does it go so i know how far to look down the harness

 

There is too many people here going back and forth. I'll let the other poster who was helping handle it.

BTW, I do believe that the orange vacuum hose is to close off the outside door for MAX AC so you have no outside air coming in.

 

that's possible.. All I said was it was the easiest one to get to

 

Alright thank you

 

Who knows, maybe if the OP follows that line and finds the fesh air door he might see a bunch of animals and nuts and berries fall out of it!

I'll still help but between two of us we are sending you in different directions.

 

i'm wondering if somehow his evaporator is clogged up....

 

Do you think that may be the problem because the air still gets warm and everthing it just doesnt blow.

 

Thats what I was thinking, why I asked about anything behind the fan when he had it out. It would make the air flowing slower. But the blend doors switching while on and off the throttle could be due to vacuum. And defrost being default if there is no vacuum.

 

So there could be no vacuum but would that have anything to do with heater core

 

I bet it's mostly a vacuum problem... If he can hot wire the blower motor, start the car, and feel the air coming out the defroster vents, then He should first fix the vacuum problem before he starts fretting about a plugged up evap

I thought his problem might be similar to what I have with my car, but it's not...

you mind taking a look at this?
https://www.thirdgen.org/forums/inte...ater-core.html

 

so look for vacuum leak first then if not check heater core

 

this is my bet...

your core is fine.. but without the airflow, you're never going to feel the effects of it. Your airflow is messed up

 

ok

 

This poster seemed to be having similar issues with the vents changing.
https://www.thirdgen.org/forums/cool...-problems.html
But was unable to resolve that issue. Maybe you will have different results

 

 

there was not power at either one of them