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Premium Member
'72 350SL, '85 300D, '98 E320, '19 Subaru Outback (sold '14 GLK250)
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10,083 Posts
Discussion Starter #1
My wife drives our 98 E320. Last night when she came home, she asked if a fan should still be running after car is shut off. I said Yes, but didn't go out and check. (We have early winter here and car is outside!). Up until then car had run and started normally (during her grocery shopping trip)

Today, we were late for an appointment so rushed out to go in the E320. It was totally dead. Could not even turn fob to try and start. I checked the voltage under the hood (Jumper posts) and got almost nothing - maybe 0.3V. I have one of those Lithium starter packs, but they don't work below 2V. Besides I am concerned about using that on the W210. Gave up on that idea.

I pulled the battery and it showed about 5 or 6V. It is presently charging.

With that background, finally a question or two :)
  • Is it likely that the electric fan would have run on a day when temperature was about 30F?
  • If it was the electric fan running, is there a relay somewhere that should have shut it off?
Maybe it was something else that was running? There is that blower on the front of the engine? Motor for throttle? A/C blower. Electric coolant pump?

I guess I should find out once I replace the battery. I will load test it first. It is 9 years old. The smart charger is going nuts - up to 9amps.
 

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Premium Member
1998 E320 base sedan @ 160kmiles
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6,015 Posts
Possibly a bad blower regulator. Just measure the resistance at the jumper points while the battery out.

No fan should be running with the key out, except if you activate the REST function to keep the car warm, and that is the blower motor. The blower motor (in REST mode), is turned off if the voltage goes down below 11V.
 

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Premium Member
'72 350SL, '85 300D, '98 E320, '19 Subaru Outback (sold '14 GLK250)
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10,083 Posts
Discussion Starter #3
I need to bring myself up to speed on W210 again!

Do you mean the ventilation blower under the dash? I recall changing that out years ago. I asked her if she it was that fan she had heard, but she didn't think so. But it could have been. Could it keep running once car was turned off?

When you say jumper points - where are those?
 

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Premium Member
1998 E320 base sedan @ 160kmiles
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6,015 Posts
I meant jumper posts, sorry. The posts you measured 0.3 V.

The blower regulator is in series with the blower motor, and it controls the speed of the blower fan with pulses. Normally it is supposed to have very high resistance with the key out, but if it goes bad, it becomes conductive (not fully). So the blower fan nay turn slightly, and you may barely hear it, and no noticeable air flow due to flap positions. Easy to disable, but you need to remove the bottom dash tray under the blower, and remove the connector at the passenger door side.

If it is the font aux fans, due to fan module going bad, then you can remove the fan connector where the fan unit is, and see if the resistance you measure changes.
 

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Premium Member
'72 350SL, '85 300D, '98 E320, '19 Subaru Outback (sold '14 GLK250)
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10,083 Posts
Discussion Starter #5
OK - that makes sense. Check if there is a short on those terminals with everything off and no battery? Dark outside already (and cold!) so that may have to wait until tomorrow. I did try and meter read 91 or 9.1 or ?? Couldn't read the units (it is autoranging). Not open circuit though.
 

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Outstanding Contributor , SDS Guru
1998 MB E300TD, 1997 MB E36 AMG, 2001 MB E55 AMG
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3,405 Posts
Most likely the blower fan resistor went kaput. Rather common problem.

Charge the battery and listen and see if you hear the fan.
 

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Premium Member
'72 350SL, '85 300D, '98 E320, '19 Subaru Outback (sold '14 GLK250)
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10,083 Posts
Discussion Starter #7
Ok,
Battery charged back fully and load test says it is good.

I checked resistance at battery terminals and at posts under hood. 9.5ohms and 10.1ohms. So if I hook battery back up I will get ~1.2amps draw - like a 14W light bulb?

So I guess that should be OK for a test and to get car started and into garage?
 

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Premium Member
'72 350SL, '85 300D, '98 E320, '19 Subaru Outback (sold '14 GLK250)
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10,083 Posts
Discussion Starter #9
OK, I will install battery and move car. Is there a fuse for the blower motor/resistor that I could remove first to prove that is the problem? I can pull the plug as you suggested, but need to get car indoors to work on getting the dash panel off.
 

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Premium Member
1998 E320 base sedan @ 160kmiles
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Unfortunately, no fuse. The blower regulator is connected to the ground and the motor, and the motor is hardwired to + supply via z7/30 red line to X4 positive supply terminal block. Look for A32 in the diagram. m1 is the blower motor, n1 is the regulator.
 

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Premium Member
'72 350SL, '85 300D, '98 E320, '19 Subaru Outback (sold '14 GLK250)
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10,083 Posts
Discussion Starter #11
Ok thanks. I had been looking through diagrams as well and couldn't find a fuse. Ok, time to go and check it out.
 

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Premium Member
'72 350SL, '85 300D, '98 E320, '19 Subaru Outback (sold '14 GLK250)
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Discussion Starter #12
Ok, so it was blower. It runs continuously once battery is connected. started car and put in garage. No heat in there, but better than outdoors! I took lower panel off and disconnected the blower. So we could drive car, but presumably no heat.
I had installed the W140 resistor some years ago. After lunch, I will have a look at that and maybe remove blower. I need to go back and see what I did and what part I installed. Memory is bad. Is that w140 resistor also the regulator?
 

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Premium Member
1998 E320 base sedan @ 160kmiles
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6,015 Posts
It is not a resistor as such, W210 or W140., it is a regulator with solid state circuits in it, mainly a voltage to pulse-width modulation converter and the drive transistors configured as Darlington pair.

You obviously have the "old style" like mine was. I replaced mine with the new style (porcupine heat sink), and a new plastic frame blower fan.

You can get the old style regulator from Amazon or EBay, starting from Chinese stuff for 20+ bucks, or Behr, Bosch, Hella brands for considerably more. Get some heatsink compound if not already supplied with the regulator..

https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=9140010179&_sacat=0
 

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Premium Member
'72 350SL, '85 300D, '98 E320, '19 Subaru Outback (sold '14 GLK250)
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10,083 Posts
Discussion Starter #14
The regulators in your link seem to be W210 regulators. I have to try and find my original order, but I believe I changed to the W140 regulator with part number 1408218351. Like this one:

Looking at shipping dates that one is no doubt coming from China! I would buy elsewhere.

One question: When regulator fails, is it likely it would fail ON. My original one just malfunctioned and others had blower not work at all. In case new regulator does not fix problem, I wondered if a sensor or something else could be the cause.
 

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Premium Member
1998 E320 base sedan @ 160kmiles
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6,015 Posts
Yeah, if you made the mod for W140 to fit in with the wiring, you should use the W140 type.

The regulator can fail in many modes, my last one failed to provide high speed blower power (low resistance), and the previous one, 8 years ago, failed with very low blower speed.

You can test the blower regulator in circuit, by increasing the blower speed up and down from the controller. If no response (same speed), in all likelihood the regulator is bad.

You can also measure the resistance across the ground connector and the blower motor connector with the regulator completely removed. If not high resistance, then it is bad.
 

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Premium Member
'72 350SL, '85 300D, '98 E320, '19 Subaru Outback (sold '14 GLK250)
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10,083 Posts
Discussion Starter #16
I checked using the climate control fan speed control and it has no affect. This with Auto actuated. If I turn Auto off, the speed increases and it blows harder.

I took the blower out. As you can see here, the wire colors don't match the diagrams. Other than the wire going to the motor, the wires from regulator should be brown (ground), white/pink and red/black. We have black, red and yellow. The original harness is same as the regulator and also has the Red wire to the motor.

I checked the original How-To on MBWorld and they had same colors. Wiring diagram does say that Pin 1 is ground, so that would be the large black wire.

Ok, assuming Blue & Black are the connections to check - My regulator measures 6.5ohms. Not very high.

Not looking good to get one here quickly. May have to wait until we are in SC in January. (We have a couple of other cars we can use)

I bought the previous one from FCP - Supposed to have a lifetime warranty! Lasted just 7 years. Not too bad for $34 at time.


2613369
 

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Premium Member
1998 E320 base sedan @ 160kmiles
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6,015 Posts
Yes, blue and black The thickest two. The thin red is the power supply for the regulator (switched on with key in position 2) and the yellow is the control wire (from the controller).

Make sure that you use the heatsink paste. Although the W140 heatsink is bigger with more contact surface, it will not last long without the paste.

Is there a plug where the wiring harness is connected to the regulator body?
 

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Premium Member
'72 350SL, '85 300D, '98 E320, '19 Subaru Outback (sold '14 GLK250)
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10,083 Posts
Discussion Starter #18
Yes, I used heat sink paste previous time.
And, yes, there is a plug socket on regulator body. I used pins there to double check the resistance.
 

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Outstanding Contributor , SDS Guru
1998 MB E300TD, 1997 MB E36 AMG, 2001 MB E55 AMG
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3,405 Posts
You could buy the ones off ebay, change your sorting to "closest" and you'll find one or two sellers that are actually located in the US.

I did this last time, got it in couple days.
 

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Premium Member
1998 E320 base sedan @ 160kmiles
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6,015 Posts
He lives in Canada which makes it longer. Amazon.ca would be better I think to get one from.
 
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