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1994 E500 blower stopped working
- Thread starter Lavaone
- Start date
I might add that if the strip fuse is a hairline crack you "might" got some continuity. Generally, when that fuse goes you will not have any fan. Fuse check first, then PBU inside, then unfortunately you need to check voltage to the unit itself, then at the resistor. Search is your friend it is well documented.
If the fan is blowing at low speed, but will not change speeds when you press the max / min buttons on the console... most likely the regulator has died. Or, if it only goes between min/low speed and medium-ish, that also indicates a failed regulator.
If the 30A strip fuse was bad, you'd get zero fan.
Regulator for "facelift" cars (with cabin filters) is MB part number 1248212151, and is NLA from MB.
Unfortunately, they also seem to be unavailable on the aftermarket, too, with few exceptions (such as Vemo) for Chinese-made parts, at exhorbitant prices. Be prepared to pay well north of $300 for an aftermarket blower motor regulator/resistor.
If your car is a pre-facelift car, you can get the KAE or the ACM blower regulator with no problem. But unfortunately it doesn't retrofit to the later cars with the cabin filters.
Unfortunately, they also seem to be unavailable on the aftermarket, too, with few exceptions (such as Vemo) for Chinese-made parts, at exhorbitant prices. Be prepared to pay well north of $300 for an aftermarket blower motor regulator/resistor.
If your car is a pre-facelift car, you can get the KAE or the ACM blower regulator with no problem. But unfortunately it doesn't retrofit to the later cars with the cabin filters.
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that's a junk, no-name part... don't expect a long lifespan.
Looks like all the name-brand regulators are either NLA or on extended backorder. There's a bunch of Vemo brand regulators for ~$250 but there are no photos of the regulator itself to see if these might be OEM (Bosch), or more rebranded cheap junk at a far higher price.
You could gamble on this "MTC" (Mission Trading Company) brand part from ECS, which has a lifetime replacement guarantee... it's very likely the same cheap junk, but at least you'll get free replacements!
My post facelift car had no low speed operation because the bronze bearing seized on the shaft. If you used high speed it was enough to overcome resistance and the bushing actually turned in the housing. I was dreading the same thing that my blower module failed because it outright failed for a couple days but then came back to life. New blower cured my woes.
My blower has completely stopped. During the ride home immediately post-failure, cold air came out the vents. I thought I heard it blowing at low speed. In retrospect I may have imagined it. (I have very poor hearing resulting from late-disseminated Lyme.) Now nothing - sounds, air, or otherwise.
I’ll commence the search for analysis and repair once I get back.
Gerry, what’s today’s (2024) cost of deferred maintenance? A lot more than 10k if the last single legs now cost $2k.
You guys who are rightfully snickering at the low cost part have no idea how thrilled I was just to see a part was actually available, never mind the silly price. The abject terror summoned each time I read NLA is growing exponentially - I feel I’m driving on borrowed time (miles?) and that a fender bender could mean she’s totaled!
I’ll commence the search for analysis and repair once I get back.
Gerry, what’s today’s (2024) cost of deferred maintenance? A lot more than 10k if the last single legs now cost $2k.
You guys who are rightfully snickering at the low cost part have no idea how thrilled I was just to see a part was actually available, never mind the silly price. The abject terror summoned each time I read NLA is growing exponentially - I feel I’m driving on borrowed time (miles?) and that a fender bender could mean she’s totaled!
Now that’s funny!
Found the fuse (great directions, thanks!) and it looks fine. Will test it but it doesn’t appear probable that’s my issue.
I finally replaced my hearing aid’s consumables so I can hear clearly and listened to my blower. If I hit any buttons that should activate the fan I get a very faint whistle noise. No matter the speed, ac or defrost.
Any ideas before I start tearing things down?
Any ideas before I start tearing things down?
It's likely the fan motor bearing you are hearing. I believe the gurus advice is change the regulator while there as an old regulator can cause a blower motor to fail. It's not terribly difficult to replace them but as you know you may have to settle for cheap parts.
Do you get any airflow (vs key off)? Trying to figure out if your blower is running on low speed, or not at all.
Only other way to tell is expose the blower and look for it turning with the key on / low speed selected.
No airflow. I get it - gotta get into the guts of it all. I’ll use search to find out which blower and cheap regulator part that are available are best choices.
Doesn’t seem quite right to complain about having no AC while at the beach. Definitely a first-world problem.
Doesn’t seem quite right to complain about having no AC while at the beach. Definitely a first-world problem.
Drove home hoping parts were here and I could tear down and replace blower and regulator. Regulator will be here today, Blower is still in Phoenix.
Weather was rainy and humid. If I put the ac/heater controls on ac mode, I got zero air flow. When in defrost mode, warm air flowed. If I put it in economy mode, cool air flowed out center vents while hot air flowed out drivers side vent. (Couldn’t check passenger side while driving down 495.). Didn’t seem fan worked in any mode except the whistle mentioned previously.
First question: do these updated symptoms point to anything other than blower / regulator?
Second: are simple continuity checks adequate for the fuses? M
As always, thanks in advance!
Sweating it out in northeastern MA,
Weather was rainy and humid. If I put the ac/heater controls on ac mode, I got zero air flow. When in defrost mode, warm air flowed. If I put it in economy mode, cool air flowed out center vents while hot air flowed out drivers side vent. (Couldn’t check passenger side while driving down 495.). Didn’t seem fan worked in any mode except the whistle mentioned previously.
First question: do these updated symptoms point to anything other than blower / regulator?
Second: are simple continuity checks adequate for the fuses? M
As always, thanks in advance!
Sweating it out in northeastern MA,
If the fan never turns on, it's the blower / regulator, OR the +12v power to those items.
If the fuse is physically removed, yes.
Yes, with inflation and a lot of time since I made the initial "deferred maintenance" prediction many years back, as well as the NLA and difficult parts situation, the new rules are as follows:
<100,000 miles = $20,000 of deferred maintenance
100,000-150,000 miles = $25,000-$35,000 of deferred maintenance
150,000-200,000 miles = $35,000-$45,000 of deferred maintenance
>200,000 miles = $50,000+
** Note that above prices are for dealer labour + MSRP parts prices.
** Independent shop labour can reduce above numbers by 20-25%
** DIY labour + discount factory / quality aftermarket prices can reduce above numbers by 50-60%
If you don't believe me, please check my Top-End Refresh thread (this was just engine bay items) and the amount of time, labour and parts that were required for this. My car at the time had around 140K already well-maintained miles on it. I would put the total parts and labour for my work at $25,000.
If you don't believe that the numbers above are accurate, I am 110% sure that @jhodg5ck and @Klink will be very happy to confirm them, based on real-world experience and their shop pricing.
Switch the prices (appr
I don't doubt your estimate one dollar! I read your top-end refresh and almost fainted. I love this car but it's like holding a grenade in one hand and trying to get the pin back in with the other in the dark while walking on a rolling log in a fast moving current.
Blower and regulator arrived from separate vendors. I've received socks packed better with more protection than the regulator which came wrapped solely in a bunch of brown paper and clear cellophane tape. The blower was well packed and protected, I left it in its "throne" while:.
just for giggles I decided to take out and check the inline fuse continuity. It came out in two pieces. I've seen someone else's pictures of the same. So before I install anything I have to get a fuse in and see if that was my root cause.
just for giggles I decided to take out and check the inline fuse continuity. It came out in two pieces. I've seen someone else's pictures of the same. So before I install anything I have to get a fuse in and see if that was my root cause.
Self-created disaster! I dropped yet another socket into the tool sucker engine undercover. Left hood like an idiot and jacked car up to remove cover and retrieve socket. Hood met ceiling and tweaked a bit. Closed hood to ascertain damage. None to hood except I can't re-open. Cockpit pull opens and exposes to safety latch. Pulling on safety latch detaches driver side but seems passenger side is stuck.
Any diagrams or advice gratefully accepted.
Any diagrams or advice gratefully accepted.
Request rescinded, I got the hood open. Kept going and got the blower out. Would like to test with old regulator but am awaiting strip fuse from AZ. Closest MB dealer with part is in White Plains, NY.
(Hmmm, 8 hour / 400 mile round trip at best, $1.00 in tolls and 40 gallons of gas (Silverado 2500 HD WT gets ~10 MPG). Guess I’ll wait.)
Maybe I should have considered paying a bunch more to ship a part that cost less than 1 buck per but lopsided thinking is a hallmark of being human after all.
I did jack the car up (with the bonnet in an almost closed position) and pulled the underclothes off only to find the missing 10mm socket was not there but I did find a bunch of small (3/4”) rocks.
(Hmmm, 8 hour / 400 mile round trip at best, $1.00 in tolls and 40 gallons of gas (Silverado 2500 HD WT gets ~10 MPG). Guess I’ll wait.)
Maybe I should have considered paying a bunch more to ship a part that cost less than 1 buck per but lopsided thinking is a hallmark of being human after all.
I did jack the car up (with the bonnet in an almost closed position) and pulled the underclothes off only to find the missing 10mm socket was not there but I did find a bunch of small (3/4”) rocks.
A little comiseration may be in order. Over the last week while working on the MB I raised the lift and when it stopped the trunk that was partialy open (for the charger) opened completely hitting the AC duct. That will polish out. I also dropped a clip, not once but twice on the garage floor leading to 30 minutes of searching and cussing.
If it was easy everybody would be doing it.
If it was easy everybody would be doing it.
The fuses arrived yesterday so I drove back home again to install. Nogo on blower.
Swapped blower out but not regulator - to do fault isolation (I know I’m reaching a bit when I call shotgunning probable parts FI). New blower installed and runs. Thought about whether I should replace regulator with the cheap unit I bought. Decided against it.
Realized after I turned ignition on to test blower op that wiper didn’t move to rest position. That’s when the realization hit I that I had forgotten to re-connect the wiper.
Took it all apart again to plug wiper back in.
Tested good. Everything working. Woo hoo!!!
Drove back to beach this morning. 50 miles later blower stopped blowing. I am gobsmacked. Now what?
Regulator should play no role as new blower worked great albeit for only an hour.
Plan to drive home and rip it all out again this weekend.
Anyone want a 1994 E500 cheap?
Make me an offer.
Swapped blower out but not regulator - to do fault isolation (I know I’m reaching a bit when I call shotgunning probable parts FI). New blower installed and runs. Thought about whether I should replace regulator with the cheap unit I bought. Decided against it.
Realized after I turned ignition on to test blower op that wiper didn’t move to rest position. That’s when the realization hit I that I had forgotten to re-connect the wiper.
Took it all apart again to plug wiper back in.
Tested good. Everything working. Woo hoo!!!
Drove back to beach this morning. 50 miles later blower stopped blowing. I am gobsmacked. Now what?
Regulator should play no role as new blower worked great albeit for only an hour.
Plan to drive home and rip it all out again this weekend.
Anyone want a 1994 E500 cheap?
Make me an offer.
Yes, if you apply 12V directly to the blower motor, it should run at max speed.
McParts / FLAPS = Friendly Local Auto Parts Store. Basically any part store chain nearby... NAPA, O'Reilly, AutoZone, Carquest, Pep Boys, etc...
In rare cases, a new blower can kill an old regulator, or so I've heard (never experienced this personally).
I forget, have you tried gently turning the ignition switch/key back (CCW) slightly? A worn ignition switch can cause a no-blow situation. If wiggling the key makes the blower turn on/off, the root cause is the ignition switch. This isn't common but a few different forum members have encountered this. It's more likely on a higher-mileage car with more cycles (more wear) of the ignition switch.
How cheap? Don't tempt me, lol!
I was thinking ignition switch too. While it’s not working would be the time to put a test light on the terminals behind the three vacuum pods where the regulator plugs in. There are three terminals—one ground, one 12v and one variable depending on cooling demand. Be aware that if the ignition switch is bad you can still measure 12v even thought there’s not enough current to drive the blower motor. That’s where a test light or another motor would help.
Just read the thread again, in post #4 the regulator was called out as probable. Had I read that one more time again before starting out last weekend to replace the blower I would have swapped it out first and tried it with the old blower.
Definitely to be replaced this weekend.
The ends of my fingers are sore from trying to hold onto and not lose these small screws.
Noted that prior work by trained mechanics has resulted in broken tabs, missing proper fasteners, missing clips, etc. I don’t feel as bad about the 10mm socket.
Definitely to be replaced this weekend.
The ends of my fingers are sore from trying to hold onto and not lose these small screws.
Noted that prior work by trained mechanics has resulted in broken tabs, missing proper fasteners, missing clips, etc. I don’t feel as bad about the 10mm socket.
Is the blower motor completely dead, not running at all (first post) or is it running at low speed only (second post)? These are 2 completely different failure modes.
Check with the car stationary, not in motion! When driving there will be some air pushed through the vents due to air pressure on the inlet grille at speed. Don't mistake this for the blower running.
I did do all the following with everything stationary.
Okay, disassembled to point where I could observe blower. Blower ran only in low speed. Dicked around with ignition switch, no impact there. Checked and found wire connection to blower wasn't solid. Made solid connection and blower seems normal but can't really tell - no real contrast tho assess blower blowing properly versus blower running weakly, though it seemed weak in the car.
Separately, applied 12V battery power from my lawn tractor to old blower and it ran solid. I guess I have a spare.
Following everyone's advice, I started looking to change out regulator / resistor but hit snag. Given its the 3rd time I've stripped everything down to the blower that part took about ten minutes as I followed "How-To" at HOW-TO: Replace W124 Blower Motor & Regulator (Pre-Facelift Models) | "HOW-TO" Tutorial Articles. But, like a TV series that ends due to low viewership, it ended with a "you can take it in from here" regarding actually removing the regulator / resistor.
Hmmm. I felt like a F16 pilot trying to land on an aircraft carrier at night for the first time. After 1/2 hour of removing various screws and yanking on things hopeful that I wouldn't break them I reached the conclusion that there was no way that sucker was coming out without dissembling the entire box. I thought "maybe I can just reuse the old heat sink" but thought I was taking the easy way put.
Luckily, I found this:
What is thermal compound? Do I have to wait another week to get some?
Okay, disassembled to point where I could observe blower. Blower ran only in low speed. Dicked around with ignition switch, no impact there. Checked and found wire connection to blower wasn't solid. Made solid connection and blower seems normal but can't really tell - no real contrast tho assess blower blowing properly versus blower running weakly, though it seemed weak in the car.
Separately, applied 12V battery power from my lawn tractor to old blower and it ran solid. I guess I have a spare.
Following everyone's advice, I started looking to change out regulator / resistor but hit snag. Given its the 3rd time I've stripped everything down to the blower that part took about ten minutes as I followed "How-To" at HOW-TO: Replace W124 Blower Motor & Regulator (Pre-Facelift Models) | "HOW-TO" Tutorial Articles. But, like a TV series that ends due to low viewership, it ended with a "you can take it in from here" regarding actually removing the regulator / resistor.
Hmmm. I felt like a F16 pilot trying to land on an aircraft carrier at night for the first time. After 1/2 hour of removing various screws and yanking on things hopeful that I wouldn't break them I reached the conclusion that there was no way that sucker was coming out without dissembling the entire box. I thought "maybe I can just reuse the old heat sink" but thought I was taking the easy way put.
Luckily, I found this:
"The 94-95 models with dust filter have a COMPLETELY different design for the heat sink. You don't even need to remove the 94-95 heat sink, the small regulator sits on top and can be unscrewed easily while the heat sink remains in the car. 100x easier than the early cars. I would not even bother removing the heat sink on a 94-95, just clean the surfaces and apply fresh thermal compound. More photos at this link."
What is thermal compound? Do I have to wait another week to get some?
Gerry, I was reluctant to swap in the new $40 'imported from somewhere other than Germany' regulator. Odd symptoms also added to my conundrum. I can only hope to and learn. Thank you as always for the advice.
Each time I disassemble a newly affected functional area, it's a first. And I did replace the fuse!
Standard / expected symptom with a failed regulator.
Ignition switch is only suspect when the blower does not run *at all*... zero speed even with good fuse/wiring/etc. Since the blower was running on low speed, the ignition switch is OK.
Replaced resistor / regulator after tearing everything down for the third time. Everything working fine.
Lesson learned - read thoroughly about all symptoms before starting out!
Other lesson learned: cheap parts is as cheap parts does. Good thing I didn't need to swap in the heat sink. The 3 mounting holes weren't threaded. Oh, and the metal transistor mount package was just a hair oversize and would not fit. As I had already wrecked my fingers againf getting that rubber firewall plug in place before finding that out, I ruled out taking it out and over to my workshop to grind down a mill or so off the metal mounting pad and instead set about Sneaky-Peteing the three screws in by first heading off to Home Depot for one longer M5 0.8 bolt with which I could get a purchase on the 3rd hole and then working all three until it settled in. Plastic - danger!
So now: my fingertips are killing me as every heartbeat at night the last two days reminds me; I've got a suspect infected cut on my right forearm from a bite one of those nasty clips give me; and I have a smile from ear to ear because I DID IT MYSELF! Of course, I wasn't ever alone, so I wanted to close out by saying again, thank you all for your guidance and patience with me.
Charlie
Lesson learned - read thoroughly about all symptoms before starting out!
Other lesson learned: cheap parts is as cheap parts does. Good thing I didn't need to swap in the heat sink. The 3 mounting holes weren't threaded. Oh, and the metal transistor mount package was just a hair oversize and would not fit. As I had already wrecked my fingers againf getting that rubber firewall plug in place before finding that out, I ruled out taking it out and over to my workshop to grind down a mill or so off the metal mounting pad and instead set about Sneaky-Peteing the three screws in by first heading off to Home Depot for one longer M5 0.8 bolt with which I could get a purchase on the 3rd hole and then working all three until it settled in. Plastic - danger!
So now: my fingertips are killing me as every heartbeat at night the last two days reminds me; I've got a suspect infected cut on my right forearm from a bite one of those nasty clips give me; and I have a smile from ear to ear because I DID IT MYSELF! Of course, I wasn't ever alone, so I wanted to close out by saying again, thank you all for your guidance and patience with me.
Charlie
