TheIgnitious

I can't seem to get my heater to work when switched on heat. I have done the interior switch fix, and I don't think it's a vacuum leak. I mean you never know. It blows heat when I have it on any other setting, and does not differentiate between cold and hot. (I'm assuming because I have no A/C) so it's always blowing heat unless I have it off. Any suggestions to any of these problems? I also can't get it to blow very hard.. I have a "new" motor that I pulled off an 84 but I'm not sure how to proceed on these problems.

Annihilate

iTrader: (1)

I have a similar issue. Except it doesn't blow hard. Try switching to vent and put your lever all the way to cool. It should blow cool air in. However if it is the middle of summer or really warm out, all you would be doing is blowing the warm air outside in. But if someone can help me figure out why my heat isnt blowing hard through the vents that would be great.

TheIgnitious

I found that when I turn my switch to heater it actually blows out of the bottom vents (didn't notice till last night) and I'm assuming it's not getting hot very fast one because I have a carb, and two I drilled my thermostat to keep it from overheating. (For some reason these cars couldn't keep a 350 cool enough) I have to turn mine on max then all the way to hot to make work. But I have heard of some people putting a switch to the water directed on the heater hoses because they can not get their vents to close. If the max all the way to hot doesn't work, it could be vacuum I suppose. There is usually an annoying hiss along with that though

Maverick H1L

iTrader: (8)

First, there is a second vacuum switch that controls the heater control valve on the bottom of the control head in A/C cars. It's either on or off, there is no between setting.

Second, make sure you have the temp control door cable adjusted properly to give you full travel of the door between full cold and full hot.

Third, if you're having issues with just the floor vents, make sure that the foam insulation blocks between the duct that's screwed to the heater module and the console are still there and aren't leaking. Also check for restricted vacuum to the lower mode vacuum motor.

TheIgnitious

How would you go about adjusting that cable? I didn't know you could do that honestly. That may be my problem right there. And I'm assuming the lower one you speak of is the one on the pass side right inside the dash?

Maverick H1L

iTrader: (8)

When you take off the panel under the dash (if you have one, some cars don't), you will see the lever for the temp control door on the bottom of the heater module. There is a clip on it that retains the clip that is attached to the control cable. You loosen the metal clip on the cable (been a while since I did this so I've forgotten exactly HOW) and slide the cable through the clip until you get the cable AND the control lever to the full HOT position. Release the clip to stay on the cable, and slide the control lever to full cold and hot several times to make sure that the adjustment is correct. You should hear the door "slamming" against both stops as you move the lever.

The lower heater control vacuum motor is the one with the BLUE vacuum hose on it. Unfortunately, you would need to take the dash out and take apart the heater module if the motor needs to be replaced so you can access the screws holding the motor arm to the actuator door lever. Which is why you should make absolutely sure you're getting a full vacuum signal to the motor before deciding whether or not the motor is bad.

TheIgnitious

I'm fixing to try the cable.. I know I'm probably questioning the crap out of you, but when it comes to this a/c / heater stuff I'm clueless.. Give me a motor and trans to stab and I'm good. Anyways, how would you test that motor without taking the dash apart. I'm doing seam sealer right now, so I have console and bottom part of dash out (not heater box) and also, I noticed the heater box is kind of lipped so it seals, well apparently someone tried to tinker with it in the past and it appears that lip is broken for a few inches in one spot. Would this cause heat and blowing loss?

EDIT- I was also told that some sort of louver (there is two of them) or something of the such isn't opening on the blower motor, which is usually something vacuum.. Any ideas on that??

Maverick H1L

iTrader: (8)

Do you have a MityVac (hand vacuum pump)? If so, use that to try to get the vacuum motors to move. And also use the gauge attached to check for engine vacuum coming out of the hose attached to the motor(s). There is no "louver" between the blower motor and the dash. If the blower is running, there is air circulating through the ducts inside the car, period (and even if the blower isn't running due to natural ram air flow through the cowl). May not always be the right ducts, but air is flowing through them. The only thing that may possibly be in the way of the air flowing into the car is if the car has an evaporator core for A/C. This has foam sheets attached to it on both sides and the foam can become clogged in dusty climates.

There is a recirculating vent by the heater case, that weird shaped thing bolted to the cowl with the vacuum motor attached to it and is a black frame with a white plastic door.

Question: Do you have the full non-A/C system or do you just have the A/C control head and ducts without the engine compartment BS (like I do)?

TheIgnitious

I do not have a hand vacuum pump, and I have a full a/c car, I just don't have compressor hooked up. Needs a conversion done. Evaporator isn't a problem, I've removed and cleaned it. The only thing I have not adjusted was that cable. Just never got around to it today. I looked at it and I'm still not quite sure? When you put it on cold it pushes towards the rear of the car. When put on heat it pulls to the front. What exactly must I do? Put it on cold and pull more tension on it? I'm not sure what the recirculating valve you said is, it doesn't ring a bell on my firewall

Maverick H1L

iTrader: (8)

You release the clip on the cable with the selector lever in the full HOT position and push the door lever towards the cable sheath until it can't go any further. That will put the door in the full hot position along with the temp control lever.

When you're looking at the bottom of the heater module, look to the right of the temp control door cable and lever. You will see an ORANGE vacuum tube that leads to the recirculating door. It is in the extreme right hand corner of the firewall under the dash, near where the engine wiring harness comes through from the side behind the fender. Not that this matters in your case.

Also, turn the system on HI and disconnect the purple wire from the blower motor. Check the voltage between this wire and ground. You should get full battery voltage.

One of the major problems with these old cars is the way GM sealed the HVAC system... With cheap foam. This foam gets old and disintegrates, and the seals are lost, so air is blowing out of the ducts all over the place except where you want it.

I guess I should ask you to be more specific...
1. Do you have HOT air coming from the vents, or lukewarm, or any other temp with the temp controls set to HOT?
2. Does the air flow change with the movement of the selector lever between defrost, dash vents, floor vents, dash and floor vents, and does the pitch of the air flow (the blowing air noise) increase when the lever is put in the MAX position (recirculating door opening right directly into blower input hole)?
3. Do you have next to no air flow with the blower switch in the LO position? Or none at all? Do all of the switch levels work?

TheIgnitious

I have lukewarm coming from my vents, but I think that may be because my motor is so cold natured. But, at the same time, when my temp gauge says a little above 100 degrees it does not feel like it is. The best setting I can get it to blow on is MAX and it blows through the dash vents. I know the vents change when I change settings. It probably has a sound change from the others to max, but I can't exactly remember. I have a little air blowing on low, it works on the next setting up, but on the 3rd setting it shuts off. That's one problem I have had, when it hits high setting, it bangs like it gets a random voltage charge at first. I have a feeling this deals has something to do with my blower blowing when the car is off.

Maverick H1L

iTrader: (8)

1. Go through the blower motor voltage check as I described above. You should see next to no power on LO, a bit higher on 2, and you will probably see nothing at all on 3 (since the blower shuts off). The gray thing mounted vertically in the blower case to the right of the blower motor is the blower resistor pack, and it probably needs to be replaced, but make sure that you have power coming through the non-purple wires at the connector before you go out and replace the resistor pack. If you don't have power on any of the wires with the switch in 3 (not the purple wire, mind you, as that is the output to the motor), then the switch in the control head is suspect. Also, does the blower run in HI with the car shut off or some other speed?
2. What temp thermostat do you have installed?

MAX only comes through the dash vents, same as VENT, but this setting opens the recirculating door so that the air coming out is either hotter or colder depending on the temp door position. BI/LEV is both dash and floor vents, HTR is floor vents only, and DEF is obvious... There will be some air flow through all of the vents at all of the positions due to the fact that some of the system diverter doors are designed in such a way that they don't fully seal with the settings of the controls (the doors aren't quite big enough to completely seal off the passages in the heater module and this is done for safety reasons).

TheIgnitious

I never have my blower below high just because it sucks so much on lower speeds, so for sure on high. I think that may be wiring to my fuse block (Dude who first had it cut out CFI wiring and other stuff needed, found out A/C wire was ran by a speaker wire). Also, it could be because of that relay, I actually already had suspicions of it for the constant running. And I have a 180 or 190 temp. Which could also explain. But now my next problem is how to heat up such a cold natured motor when it's 35 outside. Starting it 20 mins early doesn't even heat it up.

BUT on my 180 to 190 thermo I have three or four small holes drilled to attempt to cool down my 350 by allowing constant water access to it. Now that I have a 305 I can try another thermostat if it'll help. Just gotta figure out how cool it'll keep it. Especially with a mechanical fan and a hand made shroud

Maverick H1L

iTrader: (8)

If that's the case, take out the control head and disconnect the fan switch. With the key on, check the voltage at the brown wire in the fan switch connector and also the one in the connector on the orange slider switch. The brown wire on the orange switch is the power feed from the HTR/AC fuse and the other one is the power feed to the blower switch (connect the orange switch first as you won't get any power to the blower connector if you don't). You want as close to battery power as you can get. With any luck, the dash harness hasn't been too badly butchered.

With the engine running at around 185, the heated air should be plenty hot. Unless the heater core is partially clogged or the temp door isn't properly adjusted.

TheIgnitious

That's the thing, my temp isn't hitting that hot, just above 100 as in 100-120 in fact. Let me give you a little image into my dash wiring lmfao. It's a hot yellow wire, spliced to the thicker speaker wire, electrical taped to the brown wire that controls my switch.


The temp thing I'm going to try a non drilled thermostat and see if that works

Maverick H1L

iTrader: (8)

Yes, a new thermostat will get things hotter, but you're going to need to fix the wiring to get the blower running right. If the heater is running off of a yellow wire, then who knows what circuit it's on (and probably the wrong one if the blower keeps running with the engine off).

TheIgnitious

Yeah, I'm fixing to dive into wiring. I'll post if I have any questions, thanks!!

Maverick H1L

iTrader: (8)

I'm sorry I couldn't give you better news on the blower front...

Might help if you pulled the console out to get access to more of the dash harness. The brown wire you're looking for might still be coming out of the harness somewhere. Make sure that you can get a resistance check between the HTR fuse and the wire to make sure it's the right one.

TheIgnitious

I actually already have it out along with bottom half of dash due to a seam sealer project. Anyways, the idiots who owned the car previously couldn't find original wire. Found it dangling and spliced it, blows 100xs harder. Still doesn't work on 3rd setting, but I think that's just relay. Later this week I will probably do adjuster cable, but I had to fix the known fire hazard today

Oh and no more constant blowing. The same idiot had it wired in on the top row (all constant optionals I think) and it caused that problem.

Maverick H1L

iTrader: (8)

I hear you on the seam sealer... I had to redo pretty much every inch forward of the rear seats on my 88 after plugging a couple holes... Not fun.

Does your heater only have 3 speeds? Seems it should have 4... Lo, med/lo, med/hi, HI.

TheIgnitious

Oh man it's horrible. I had to do under rear quarters forward. And yeah, it has 4