Blower/fan question deux - only on high, now stops working

Hi there, and sorry for the repeat question, but I have a slightly different problem now.

As MANY people have noted, I too had the 'fan only working on high' thing going for many months. Didn't really bother me too much, and now I understand why (most likely the blower resistor). However, now I have a new problem: the blower STOPPED working all together tonight, and I am wondering how I should troubleshoot this. Is it a short? Is it the fan? Is it the switch?

Some other interesting observations:
- there are times that I stop the car, and the fan continues blowing, even though everything is off.
- There are times that I turn on the fan (i.e. from off to 'high'), and it wouldn't start. However, in about 3-5 sec. it would.
- I have removed the A/C panel, and it seems that everything is working there. The switch did have a lot of gunk on it/grease, which I didn't know if was a problem.

How would you all suggest that I test each one of these? Also: what safety measures should I take when working with the fan (i.e. I have an aversion to electrocution... but I realize I need some juice...).

Thanks for your help/advice.

Going to get the blower motor resistor. FYI for anyone else doing this- it is a dealer part, so don't waste your time talking to other people, just go there. Part is $13-14.

The real question now is what to do about the blower completely stopping, so if anyone has any pointers, please LMK. Thanks!

I believe a new Blower Motor Resistor will solve all the blower problems.

C.B.

so, now the blower doesn't work at all. Panel still lights up, and whatnot. I REALLY don't want to take the dash apart... is this the only way to get at the blower? Is there another point to check to see if there is a short somewhere (i.e. exposed wiring where something bad could happen?)

Thanks in advance!

I'm sorry to hear the new BMR didn't do it for you. I'm not sure about the answers to your other questions. Maybe someone else will chime in here with some help.

C.B.

Hi there,

I have a similar problem so will try to replace the resistor. Is it easy to do? Can you point me somewhere that gives me a step by step.

thanks,

Andy



Going to get the blower motor resistor. FYI for anyone else doing this- it is a dealer part, so don't waste your time talking to other people, just go there. Part is $13-14.

The real question now is what to do about the blower completely stopping, so if anyone has any pointers, please LMK. Thanks!

Hi I,
Blower always runs at least at lowest speed unless off button is engaged if you have a.c.. Resistor replacement only affects the two middle speeds. Something may be dragging on the blower wheel. On my 89 Imtap the motor with a hammer with the power to the blower on to get it started. My blower motor brushes are worn (140k miles) so torque is dropping due to poor brush contact. If i could findout how to remove the lower dash panel I would replace the motor but it's zero F outside so i'll keep using the hammer til spring.

hope this helps

qwester

I have a related question. My 98 Grand Caravan heater fan only works on high. I ordered a resistor from the dealer, but I can't figure out where the resistor is mounted. Thanks for the help!!

/\ndy

The Blower Motor Resistor in 1998 models is mounted on the firewall under the hood on the passenger side just behind and to the side of the A/C equipment. It has a tab on each side you have to fool with to get it to come out. Push in on the tabs and it should come out of the firewall and then you can disconnect the electric lines plugged into it and snap in the new one.

C.B.

C.B.

The Blower Motor Resistor in 1998 models is mounted on the firewall under the hood on the passenger side just behind and to the side of the A/C equipment. It has a tab on each side you have to fool with to get it to come out. Push in on the tabs and it should come out of the firewall and then you can disconnect the electric lines plugged into it and snap in the new one.

C.B.

C.B.


Thanks CB, Have a wonderful new year!

/\ndy

I just spent a couple of hours getting my blower motor out. Took it to an auto parts store who said they can't test it. It only works on the high setting. They said if it works on high its not the motor and to check the switch. I asked them if they were talking about the control on the dash, they said yes and that you can't get the part from them, only dealer. I'd hate to take out the center console (controls). Where can I find this resister part on my 96 Ply. Grand Voyager that has been mentioned on forums?

The blower motor resistor is located on the firewall under the hood. Open the hood and look at the firewall on the passenger side of the engine compartment. You will see a multi connector type thin that looks liek it plugs right into the firewall. It is quite possible it may look like it has sort of burned up in spots. The advice to go to the dealer for a new part is good, but I'd highly recommend going to a boneyard to get a connector in better shape if yours is (and it probably is) corroded or burned. What I did was to get a new resistor from the dealer - then went to the boneyard and cut the connector off a harness that was in much better shape. Then I spliced the boneyard connector onto my harness - soldered with one of those cool propane soldering irons, then heat shrink tubing and tons of electrical tape. It has been going strong ever since. One thing though, be sure you keep track of which wire goes where on the connector or your speeds will be out of order on the switch - and that is not worth opening the slice back up to fix. Just another custom quirk in the old van now...

That is exactly what I found, burnt plug in. It was very hard to get the plug disconnected and after getting it off I found that it had burned and melted (fused) together. I bought a new plug ($20.00) and will splice it together soon. I will use the heat shrink tubes also. Thanks for the input.

Well, I decided instead of leaving anyone who looks at this this hanging in suspense! :)

Well, here's what happened:

blower motor resistor: I disconnected the battery and I replaced the resistor, which BTW was rusted to the plug. On my 96, you can find this under the hood. I had to remove a bracket from what looks like the A/C system so I could get my hands under there. It was a simple friction clip system- no bolts or anything. Just pull it out (it actually was pretty hard to remove, but eventually came out...).

I knew the resistor was bad b/c 2 coils were burnt out... like a blown fuse (I wish I had pics...). Knowing that it was broken, I simply cut the resistor off in chunks to get a the plug, and then used 2 screwdrivers to separate the two (this happened to someone else as well.) What I mean by cut off: I basically broke off chunks of the plastic housing that went around the plug.

I replaced the reistor, it is $14 at a dealership. You can look elsewhere, but they were the only ones in town who had one. $14 is well, pretty cheap.

However, this didn't solve my problems. Fan still wouldn't come on. I assumed it was the blower motor. Contacted the dealership as only they could get this part, and it turns out new its $130. I needed this car for work and didn't have time to dicker with it more since those storms just hit. You could probably get it from a junkyard, but I didn't have time to do that. I took it to a local dealership and let them see what they could figure out.

Turns out it was a blower motor relay that was bad. They replaced it and it now works like a charm. Total cost, even with taking it to a dealership was about the same as replacing the motor.

So in summary: I had two problems. One was the 'fan only works on high or off'. Had a bad blower motor resistor, and that seemed to fix that problem. The second was the fan just quit working. New blower motor relay fixed that problem.

Well, I hope this thread helped someone out, or will help them out in the future.

In case I find this is also the problem with my 96 did they tell you where the relay is?

There are times that I stop the car, and the fan continues blowing, even though everything is off.Your Blower Motor Relay is probably frozen in the closed position - replace the Blower Motor Relay (about $8-$12) and your problem will disappear.
There are times that I turn on the fan (i.e. from off to 'high'), and it wouldn't start. However, in about 3-5 sec. it would.Again, most likely, your Blower Motor Relay needs to be replaced - it could also be your Blower Motor's worn brushes. It could also be burned or pitted relay contacts that fail to convey your instruction to START. Replace the Blower Motor Relay FIRST and see if this fixes all of your problems (it might). Check my post "1996 Dodge Grand Caravan... 101" It's all there. Though the locations of certain devices are different, the concepts are exactly the same...

http://www.automotiveforums.com/vbulletin/showthread.php?t=340871

Dodge Grand Caravan, 2001. As with many others here, my fan works on high only. This problem occurred the first time about 1 year ago. I replaced the BMR, which is located directly behind the glove box. This fixed the problem. However, about 2 months ago, the problem reoccurred. I replaced the BMR again and it fixed it again. However, the problem reoccurred last week.

Anyone know why this is reoccurring?

Thanks.

In case I find this is also the problem with my 96 did they tell you where the relay is?Every thing you need to know...

http://www.automotiveforums.com/vbulletin/showthread.php?t=340871

If this is in response to my question, that info does not address my particular situation of repeated resisters going bad.

Thanks tho

If this is in response to my question, that info does not address my particular situation of repeated resisters going bad. Thanks thoAs noted in my response, my reply was to mvollmar11, who was trying to locate the Blower Motor Relay in a '96.

There are other people on this board who are experiencing the very same recurring Resistor Block failure you describe. Unfortunately, they too are at a loss to determine exactly why this is happening. Let's think through how the AC/Heater Switch, AC/Heater Blower Motor Relay, the Resistor Block and the AC/Heater Blower Motor electrically work together.

As I understand it, the Blower Motor Relay is hot at all times and actuated by the AC/Heater Switch (in the ON position) to provide a constant supply of power (+) to the Blower Motor via its Dark-Blue wire. The AC/Heater Control Module provides the ground plane path to the AC/Heater Switch which in turn directs the Blower Motor to this path through the Resistor Block to spin the motor.

Depending on the slower AC/Heater Switch setting (Lo, M1, M2, M3), DC current (power) is drawn through a particular Resistor Block coil where the current is reduced to spin the Blower Motor at a slower speed (None for the "Hi" setting). The more a Resistor Block coil "resists" the DC current at a particular setting, the slower the Blower Motor spins.

In other words, the Resistor Block functions to deprive the Blower Motor of electricity at four different levels to provide four different speeds... all less than the "Hi" setting... that's why there are four coils on the Resistor Block. In the AC/Heater Switches "Hi" setting, none of the Resistor Block coils are used to provide the fastest speed possible for the Blower Motor.

Are you still with me so far ? :) Hang in there... I'm still thinking this through, "out loud."

We know that the main byproduct of electrical resistance is HEAT. This heat is generated by the Resistor Block's coils - MORE heat is produced by the coil that provides current for the slowest speed (Lo - more resistance), LESS heat by coils that provide power for middle speeds (M1, M2 & M3 - less resistance) and NO heat for the fastest speed (Hi - no coil/no resistance).

The question seems to be, why do these coils burn out so quickly?

Maybe the BETTER question is, why do these coils get TOO hot?

We should reasonably suspect that the hotter these coils get, the more likely it is they will burn out. I think this also means that the more POWER going through these coils, the more likely they will get HOTTER, maybe TOO hot, possibly more heat than the Resistor Block was designed to handle. Why else would some owners report melted sockets and plugs?

We know the only thing drawing power through the Resistor Block is the AC/Heater Blower Motor. Since the Blower Motor circuit is protected with a 40AMP fuse, we also know that no more than 40AMPs will ever be drawn through this circuit.

Given all of this, we might draw two conclusions...

1.) The Resistor Block (and socket/plug) is under-engineered to handle up to a 40AMP load, AND

2.) The Blower Motor is consuming more power than the Resistor Block can handle, even though BOTH devices are operating within the 40AMP maximum circuit limitation.

If I am correct in these conclusions (hopefully I am... and I invite anyone to jump onto this thread to discuss it), I see two possible solutions to this problem...

1.) Replace the Blower Motor and hope it actually consumes less power than the one it replaces, and/or

2.) Attenuate (reduce) the (+) DC power through the feed (Dark Blue wire) to the Blower Motor to consume less DC power and thereby generate less heat in the Resistor Block which is causing it to fail. A heavy-duty Varistor (variable resistor) might get the job done, though I have not looked into this as a possible retro-engineering solution. One downside I see for sure in reducing the power-draw with a Varistor through the Resistor Block to the Blower Motor... this will also reduce the speed of the Blower Motor in ALL speeds, including "Hi."

Bear in mind, I may be talking out of my butt here. Still, replacing the Blower Motor is probably the best first step to take because it is the motor itself that draws the power that is likely burning out the Resistor Block. It might be that the motor currently installed is old or maybe it's slightly different than the original/OEM motor (if it's already been replaced), drawing slightly more power, but enough "more power" to raise hell with the Resistor Block.

In the end, this is just a guess... Please report back to this thread if/when you resolve your issue. Although I am not experiencing this problem in my '96 GC, there are other owners who are! In any event, Good Luck & Happy Hunting!

My 1999 Voyager lower fan settings stopped working too (leaving only the highest and second highest settings working), and I took your advice and replaced the Blower Motor Resistor under the front hood on the passenger side firewall. It was a 10 minute job and now all my fan settings works! Thanks for the advice! I took the liberty to write instructions on how to replace this Blower Motor Resistor WITH PICTURES for others to follow. Please see my website http://www.execulink.com/~scitech/BMR/Index.htm on the full instruction. - Doug Peng [email protected] Toronto, Canada

I really appreciate all of the information in this post, it was helpful. BUT...I still have some issues. My blower works in the off and high positions only, nothing in between. I have installed a new resistor (not a 10 minute job in my van, more of a PITA). Anywho, I have pulled out the tester and I do have voltage coming to the resistor for each setting (lo, med 1, med 2) and that the new resistor does pass a current through it. All contacts are clean. I have poured over the wiring diagram and feel that I am at a dead end. I can't find any other path for the circuit. Any thoughts from anyone on how to regain my lower speeds? Thanks.

I really appreciate all of the information in this post, it was helpful. BUT...I still have some issues. My blower works in the off and high positions only, nothing in between. I have installed a new resistor (not a 10 minute job in my van, more of a PITA). Anywho, I have pulled out the tester and I do have voltage coming to the resistor for each setting (lo, med 1, med 2) and that the new resistor does pass a current through it. All contacts are clean. I have poured over the wiring diagram and feel that I am at a dead end. I can't find any other path for the circuit. Any thoughts from anyone on how to regain my lower speeds? Thanks.

Gee, your problem seems severe and I am at lost to suggest something useful. however, I also pulled out the HVAC unit from the central front dash and examined the fan switch. I must say that it is pretty robust design and I doubt it would be your problem, but you could try. The entire HVAC unit has PCB on it that looks pretty sophisticated, but the fan switch doesn't look like it is part of it (assuming you have the standard manual fan and not the climate control system) - Doug Peng