HVAC blows while turned Off?

[lothos]

I have had my HVAC turned off completely since it warmed up here. I have it set for 69 degrees, and it's right around 70 outside. Three times now I've had air blowing gently out of the vents while it's been turned off. When it happened today my black car was sitting outside in the sun.

I am low on refrigerant and need it topped off.

I remember reading in the owner's manual that it can blow air when you start the car and that is normal, but what about this? Is this normal behavior? It tends to happen after I drive a couple blocks. Turning the HVAC on and off again makes it stop.

[BodybyFisher]

There is a setting called AFTER BLOW that is utilized to stop mildue and bad odors from building up in the vent system. Check that out, not sure if that is what you are experiencing. Does it eventually shut off?

[lothos]

I'm not sure if it eventually turns off or not, it kind of took me by surprise when it happened. I turned the HVAC on and off and it stopped. I only let it blow out for a minute or two.

Can I find info about the after blow in my FSM?

[BodybyFisher]

Oh sorry, I re-read your post, its running while the car is ON... I thought it was running while the car is off.. I think there is a controller that needs replacing or your fan is shot, I will let someone with direct experience comment. In the meantime, make sure your ignition wires are NOT leaning up against your fan motor

[lothos]

Thanks for the reply, I'll go check the wires right now.

Sure enough, I had three or four plug wires sitting up against the blower motor.

I took a small zip tie, and zipped those three or four wires up against the #5 plug wire coming off the coil pack. Is that ok to do, or will that cause interference or a misfire?

[BodybyFisher]

Thanks for the reply, I'll go check the wires right now.

Sure enough, I had three or four plug wires sitting up against the blower motor.

I took a small zip tie, and zipped those three or four wires up against the #5 plug wire coming off the coil pack. Is that ok to do, or will that cause interference or a misfire?

The wires can leak high voltage or EMF and damage the components in the fan motor controller. If you have a fan that has a foil cover over the electronics, it shunts the voltage away, the newer motors have that shield. The HVAC motors tend to go bad, but I will let others with direct experience comment, I don't know if the symptom you are experiencing is related to the motor.

Personally I don't like tying ignition wires together unless they are relatively new. If they don't have wire loom over them, visit your local scrap yard and pick up some wire loom off a late model car and put it on your wires to keep them separated.

[lothos]

My plugs and wires were done last month, ACDelco all the way around. I've got wire loom around some of the plug wires, but not that section. I think I'll stop and get some wire loom tomorrow.

How do you suggest I keep the wires off the blower motor? Is there a better or more elegant solution than a zip tie? I don't want to cause any interference or misfires from tying them together. Would it be ok to zip tie them if I have wire loom on all the plug wires?

The HVAC seems to work fine other than this, so hopefully this will cure the problem. I've read that the blower motor is a pain to replace, not looking forward to it.

Thanks for your help, BBF. I really appreciate it.

[BodybyFisher]

I think you can tie them together if you use the loom, just don't tie them tightly. I am not a fan of the loom you can buy in the parts stores, it melts at a low temp. The factory wire loom is inert and does not melt easily and I prefer that. Make sure that the wires are routed and held at their attachmeent points correctly and try not to leave too much excess wire at the coil end that needs to be retained.

[lothos]

I'll make a trip to the local yard then. Thanks again for your help and advice, I appreciate it.

[jerrymac]

I just recently replaced the blower motor on my 97 Eldo , and it was a real pain in the butt. Even with the

engine rolled forward as far as it would go, the motor and wheel assembly still wouldn't come out together

because they were up against the valve cover. I stuck a sawzall in there and cut the shaft off to get it out.

Putting the new one back in was a little easier though, since you can slide the wheel part way into the duct, then slide the motor shaft on and tighten the setscrew, then slide assembly the rest of the way in.

And , by the way, a new blower motor, even from an aftermarket type parts store was $325. It seems

that Seimans is the only one that makes them. Hope BBF's advice above fixes your problem.

Of course, mine is an Eldo, the STS might be different.

[lothos]

I just recently replaced the blower motor on my 97 Eldo , and it was a real pain in the butt. Even with the

engine rolled forward as far as it would go, the motor and wheel assembly still wouldn't come out together

because they were up against the valve cover. I stuck a sawzall in there and cut the shaft off to get it out.

Putting the new one back in was a little easier though, since you can slide the wheel part way into the duct, then slide the motor shaft on and tighten the setscrew, then slide assembly the rest of the way in.

And , by the way, a new blower motor, even from an aftermarket type parts store was $325. It seems

that Seimans is the only one that makes them. Hope BBF's advice above fixes your problem.

Of course, mine is an Eldo, the STS might be different.

I found an ACDelco on rockauto.com for $280. I'm not sure if it still comes with the shield or not.

Did yours exhibit symptoms like this before it went out?

[KHE]

I just recently replaced the blower motor on my 97 Eldo , and it was a real pain in the butt. Even with the

engine rolled forward as far as it would go, the motor and wheel assembly still wouldn't come out together

because they were up against the valve cover. I stuck a sawzall in there and cut the shaft off to get it out.

Putting the new one back in was a little easier though, since you can slide the wheel part way into the duct, then slide the motor shaft on and tighten the setscrew, then slide assembly the rest of the way in.

And , by the way, a new blower motor, even from an aftermarket type parts store was $325. It seems

that Seimans is the only one that makes them. Hope BBF's advice above fixes your problem.

Of course, mine is an Eldo, the STS might be different.

I found an ACDelco on rockauto.com for $280. I'm not sure if it still comes with the shield or not.

Did yours exhibit symptoms like this before it went out?

They used to incluse the shield but not anymore - if you are replacing a first generation blower motor, you need to order the shield separately.

[jerrymac]

I just recently replaced the blower motor on my 97 Eldo , and it was a real pain in the butt. Even with the

engine rolled forward as far as it would go, the motor and wheel assembly still wouldn't come out together

because they were up against the valve cover. I stuck a sawzall in there and cut the shaft off to get it out.

Putting the new one back in was a little easier though, since you can slide the wheel part way into the duct, then slide the motor shaft on and tighten the setscrew, then slide assembly the rest of the way in.

And , by the way, a new blower motor, even from an aftermarket type parts store was $325. It seems

that Seimans is the only one that makes them. Hope BBF's advice above fixes your problem.

Of course, mine is an Eldo, the STS might be different.

I found an ACDelco on rockauto.com for $280. I'm not sure if it still comes with the shield or not.

Did yours exhibit symptoms like this before it went out?

They used to incluse the shield but not anymore - if you are replacing a first generation blower motor, you need to order the shield separately.

I didn't notice any unusual operation of the blower motor before it quit. Wife was just coming home from

work one cool rainy day and said the defrosters quit. I found the motor was bad and replaced it.

The one I bought came with new blower wheel and heat shield included.

[KHE]

I just recently replaced the blower motor on my 97 Eldo , and it was a real pain in the butt. Even with the

engine rolled forward as far as it would go, the motor and wheel assembly still wouldn't come out together

because they were up against the valve cover. I stuck a sawzall in there and cut the shaft off to get it out.

Putting the new one back in was a little easier though, since you can slide the wheel part way into the duct, then slide the motor shaft on and tighten the setscrew, then slide assembly the rest of the way in.

And , by the way, a new blower motor, even from an aftermarket type parts store was $325. It seems

that Seimans is the only one that makes them. Hope BBF's advice above fixes your problem.

Of course, mine is an Eldo, the STS might be different.

I found an ACDelco on rockauto.com for $280. I'm not sure if it still comes with the shield or not.

Did yours exhibit symptoms like this before it went out?

They used to incluse the shield but not anymore - if you are replacing a first generation blower motor, you need to order the shield separately.

I didn't notice any unusual operation of the blower motor before it quit. Wife was just coming home from

work one cool rainy day and said the defrosters quit. I found the motor was bad and replaced it.

The one I bought came with new blower wheel and heat shield included.

Did you buy an aftermarket blower or an AC Delco? The AC Delco unit I bought for the '96 about 5 years ago came with the heat shield. When the blower in my '97 failed last December, the AC Delco unit I bought did not include the shield - I had to buy it separately. The dealer raped me $10 for the shield but it was winter time and I was tired of using the rear blower to warm the car...

I lowered the front of the engine cradle and that provided enough clearance to install the new blower. The old one came out per the service manual - I removed inertial plate and rotated the blower and it came right out. The new design blower is larger and can't be installed in the reverse manner as the old one.

[jerrymac]

I just recently replaced the blower motor on my 97 Eldo , and it was a real pain in the butt. Even with the

engine rolled forward as far as it would go, the motor and wheel assembly still wouldn't come out together

because they were up against the valve cover. I stuck a sawzall in there and cut the shaft off to get it out.

Putting the new one back in was a little easier though, since you can slide the wheel part way into the duct, then slide the motor shaft on and tighten the setscrew, then slide assembly the rest of the way in.

And , by the way, a new blower motor, even from an aftermarket type parts store was $325. It seems

that Seimans is the only one that makes them. Hope BBF's advice above fixes your problem.

Of course, mine is an Eldo, the STS might be different.

I found an ACDelco on rockauto.com for $280. I'm not sure if it still comes with the shield or not.

Did yours exhibit symptoms like this before it went out?

They used to incluse the shield but not anymore - if you are replacing a first generation blower motor, you need to order the shield separately.

I didn't notice any unusual operation of the blower motor before it quit. Wife was just coming home from

work one cool rainy day and said the defrosters quit. I found the motor was bad and replaced it.

The one I bought came with new blower wheel and heat shield included.

Did you buy an aftermarket blower or an AC Delco? The AC Delco unit I bought for the '96 about 5 years ago came with the heat shield. When the blower in my '97 failed last December, the AC Delco unit I bought did not include the shield - I had to buy it separately. The dealer raped me $10 for the shield but it was winter time and I was tired of using the rear blower to warm the car...

I lowered the front of the engine cradle and that provided enough clearance to install the new blower. The old one came out per the service manual - I removed inertial plate and rotated the blower and it came right out. The new design blower is larger and can't be installed in the reverse manner as the old one.

The one I bought was aftermarket, made by Seimans. It was $325. Came with new wheel and heat shield.

[BodybyFisher]

Is this a heat shield or an shield to protect the electronics in the controller? I thought this foil/metal shield that appears to have wires running through it was to 'redirect' to ground any discharges from porous ignition wires leaking high voltage. One of the causes of failure of the HVAC motor was that discharge from ignition wires was damaging electronic components on the controller circuit board. This foil shield was a redesign, that I thought was the result of the problems they were having with the HVAC motors. I have to have a closer look at my foil shield tomorrow

[KHE]

Is this a heat shield or an shield to protect the electronics in the controller? I thought this foil/metal shield that appears to have wires running through it was to 'redirect' to ground any discharges from porous ignition wires leaking high voltage. One of the causes of failure of the HVAC motor was that discharge from ignition wires was damaging electronic components on the controller circuit board. This foil shield was a redesign, that I thought was the result of the problems they were having with the HVAC motors. I have to have a closer look at my foil shield tomorrow

Both - The shield is grounded via it's mounting bolts and it acts as a heat shield.

[BodybyFisher]

Is this a heat shield or an shield to protect the electronics in the controller? I thought this foil/metal shield that appears to have wires running through it was to 'redirect' to ground any discharges from porous ignition wires leaking high voltage. One of the causes of failure of the HVAC motor was that discharge from ignition wires was damaging electronic components on the controller circuit board. This foil shield was a redesign, that I thought was the result of the problems they were having with the HVAC motors. I have to have a closer look at my foil shield tomorrow

Both - The shield is grounded via it's mounting bolts and it acts as a heat shield.

Thanks for clearing that up Kevin

[lothos]

Well, I was driving yesterday and the blower still came on after moving the plug wires. I popped the hood and the plug wire for the #5 injector was running right next to the wire that goes to the blower motor. I moved that out of the way as well last night. Today while driving it came on again but turned off after a few seconds. I think I'm on the right track here. Going to get some of those wire covers from the junk yard in the next couple days. Hopefully that will fix it.

It's always blown out of the vents real lightly, but you can hear the motor turn on. Turning on the HVAC controls makes it blow a lot harder.

Is that shield something I can add to my existing blower?

[BodybyFisher]

I might have not been clear enough. The controller gets damaged or goes bad, once this happens its too late the damage is done. I can't be 100% that the ignition wires caused it, it could just have gone bad. Heat is also bad for electronics especially capacitors. That is probably why they put a combination heat/high voltage shunt over it.

Anyone who has had a blower motor go bad could you post how your motor acted, when it was bad?

Also, on the old cars there used to be a relay that went bad and caused the blower to stay on, does this car have a relay that goes bad?

[lothos]

Ouch, that's not going to be a fun or cheap repair. Let's hope it's a relay.

I'll go check my FSM and see if I can find anything out about that realy.

[lothos]

I looked over that chapter in the FSM and found reference to a rear blower relay, so maybe there's one for the front? I don't know enough about reading electrical schematics to be able to tell what's what. I found some diagnostic trees that might be useful in determining if it's the blower motor, wiring or the ACP. I'll probably need some help with this though.

It's my birthday today, I might not be around a whole lot this weekend. I found a 25 to 250 inch lb. Craftsman microtek torque wrench on craigslist for 40 bucks that I might buy myself as a present. I noticed some of the specs call for inch pounds when I was looking over that chapter.

I don't have a scanner, but maybe I can take a photo of some of these pages later.

[Ranger]

I looked over that chapter in the FSM and found reference to a rear blower relay, so maybe there's one for the front? I don't know enough about reading electrical schematics to be able to tell what's what. I found some diagnostic trees that might be useful in determining if it's the blower motor, wiring or the ACP. I'll probably need some help with this though.

It's my birthday today, I might not be around a whole lot this weekend. I found a 25 to 250 inch lb. Craftsman microtek torque wrench on craigslist for 40 bucks that I might buy myself as a present. I noticed some of the specs call for inch pounds when I was looking over that chapter.

I don't have a scanner, but maybe I can take a photo of some of these pages later.

Under the FWIW column, when the blower went out on my '97 I went through the diagnostics and it pointed to a bad ACM (assuming I did it correctly). ACM's are pretty reliable and I just didn't believe it and went with my gut. It payed off. The blower was the culprit. In my case however, the blower was dead.

[lothos]

Anyone know if my blower has a relay?

[lothos]

Or does anyone know what I should be looking for on the diagram in the FSM so I can figure out if there's a relay in there?

The blower turns on only when the car has been sitting in the sun for a while. It doesn't do it it at night. It seems to happen when I leave work for lunch, and sometimes when I drive home after work. If I get in the car and it's really hot, then I know it'll probably kick on. Doesn't resistance increase with higher temps? Would that cause the relay (if I have one?) to short or something?

I'm not getting any kind of code, or A/C code. My A/C also doesn't blow cold, either.