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2000 C280 Blower not turning off!

2K views 8 replies 2 participants last post by  M-BenzC280 
#1 ·
Hi everyone,
I've searched threads for the last 2 weeks (even on other sites) for find a solution to my problem. Here is are my symtoms: When the car is off and the key not inserted, my ac/heater blower keeps running. Here is what I've done so far to resolve this problem:
1. Replaced the blower - still runs
2. Replaced the regulator or resistor (everyone calls this differently) - still runs.
3. Replaced the regulator or resistor agian (thought I might have purchased a faulty one) - still runs.
4. Reset the computer by disconnecting the battery - still runs.
5. Removed and disconnected the dash climate control unit - still runs.

Pretty much all the threads I've read points to the regulator that is screwed to the blower unit but my problem isn't going away. I figured if I would disconnect the climate control unit, the blower would at least stop but that wasn't the case. Obviously the regulator is drawing power directly from something, but I don't know what. For now I'm just unplugging the blower. The fuse is fine. My question is; if the blower, regulator and climate control unit is working properly, what could be causing the blower to contiously run? Is there something else that the fuse wire runs to before the regulator? Does the fuse wire run to the climate control unit then to the resistor? If so, then my car is haunted! Please help!
 
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#2 ·
I also wanted to note, when I power up the climate control unit, my ac doesn't get cold even if I have it set top "LO" but I do hear the vent flaps open & close when I use the Auto function. The fan, unfortunately stays at one speed "HI" at all times even the control unit is off.
 
#6 ·
Wish I could help more, I checked my service cd and trying to find info in there is like finding a needle in a haystack. There are some relays under hood, left front. I know one in particular is for turn signals/hazards. Its not the size of a normal relay, it looks more like a computer module box. There may be one there as well for the AC system.

Do you have an automatic or manual ac system? If automatic, have you tried doing a diagnostic check on it?
 
#7 ·
Well, before I break down and send my car to the stealership, I thought I would give this one more shot. I took photos of my diagnosis but these are on my computer & not sure how to get them to display hear).
First off; let me recap my issue. My interior blower motor continues to blow when the my car is off (no key in the ignition). My "REST" is off as well. The only way to turn off the blower is to pull the fuse or unplug the regulator.
Today, I tried to find where each of the 3 wires that connect to the regulator and blower (both which are new) goes to and see if they are not damaged which may have cause a short.
I traced the white wire with a peach stripe back to the climate control unit harness.
Next I traced the Red wire with a Blue stripe back to the fuse box. It went to my No.29 (30amp) Fuse.
Not sure where the large Red wire goes to. I'm assuming from some power supply like the battery.
Finally, I traced the Brown wire (Ground?) to a location in the engine compartment but I'm not sure if it's the correct one since there are several brown wires grouped together.
This is what I found out where the wires go to I believe. If I'm incorrect, please let me know. I also want to state that for grins, I cut the brown wire at the regulator plug and the blower stopped. I did splice it back together.
Ok, after a few hours tinkering with car, I'm sitting here going through my options. The only things I maybe considering are 1. I may need a new climate control unit 2. The ground is faulty 3. The climate control unit harness went bad.
If I'm way off about my diagnosis, let me know. I hope someone can help me and point me in the right direction. If you need more information let me know. Thanks for reading/viewing this post! Like I said, I do have pics but don't know how to upload these since these are not on the web.
Tracy
 
#9 ·
Today, I installed a different climate control unit with same results. So, I currently replaced the blower, regulator & climate control unit. The blower still turns on when I plug in the regulator. Does the red wire from the 3 pronge regulator harness go directly to the fuse box or does go to something else before the fuse box? I'm trying to trace whre the 3 wires go to so I can check for a possible short. I know the white w/pink stripe goes to the climate control unit harness. The brow goes the engine compartment somewhere. Any help will be greatly appreciated!
 
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