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The passenger seat's seat heater will not turn on. When I (or a passenger) presses the button for heat, the 3 little lights will illuminate for approximately 1 second, and the go out. Meaning, I try to turn the heat on but it immediately turns off. The driver's seat functions normally. The only information I could find by searching was in regards to BOTH seat heaters not working and the likely cause being a weak battery. This is not the case here. Also, it does not matter if I try the heater immediately upon startup or after an hour of driving - same result, turns right off.
Can DAS/STAR (still confused about the difference here) tell if it's a switch/module/element issue? Can it even be a switch or control module (whatever is controlling it... I don't honestly know) if the driver's side is working and the switch "seems" to physically function? Can I swap the driver's side switch for the passenger's side to troubleshoot?
the heating element in the seat has a somewhat weak plug. it does get torn/ disconnected on occasion. the seat needs to be removed and the heating element plug checked. if plug is ok the heating element resistance needs to be checked. your behavior denotes the system not seeing proper resistance/ continuity from heating element
OK - I can do that. The seat was taken out to change the battery a little while ago (probably haven't used the heater since the battery was changed). I'll look underneath for connector issues. For resistance, I should be looking for something in the low, single-digit Ohm range to indicate a good element?
OK - I can do that. The seat was taken out to change the battery a little while ago (probably haven't used the heater since the battery was changed). I'll look underneath for connector issues. For resistance, I should be looking for something in the low, single-digit Ohm range to indicate a good element?
correct. anything but 0 ohms or infinity... from memory - 5-7 ohms denotes good heating element
Work has been crazy, finally get back to this. Alex, when I remove the seat, will it be obvious which plug is for the heating element (connector color or wires colors... I assume they might be a larger gauge?). I looked under the seat (from both the front and back sides) and there is a myriad of wires and connectors. I tried looking through my AllData account on the chance that they might show a location. All I could find was this picture, showing the location of the heating element, itself. Gee, thanks AllData, for showing where the heating element is that heats my butt - don't think I could have figured that one out on my own!
Brown and Blue. When taking the seat out, make sure you disconnect the battery at the negative terminal for at least 30 minutes to avoid SRS error (If you don't, you may get a scary, 'SRS malfunction, please visit workshop' message). The SRS wiring is the one with a yellow connector.
Here is an annotated diagram of what those wires do.
Cool - I was looking at that exact plug before I re-posted earlier today, thinking it might be the one. Am I correct in thinking that the plug we can see in the picture is the supply plug, and the testing can be done on the pins once the plug is removed? Or, is the testing done at the actual plug in the picture? Thanks!
I wonder why that is with the SRS issue/battery? I've seen my dealer (independent) remove my seat a couple times and he never disconnected the battery, first. Or, at least I don't think he did. Certainly not for anywhere near 30 minutes, if he did. Never got any kind of warning. Interesting.
Yes, I believe you would need to pull out the plug to test the supply side and seat side of the circuit. The 2 pins connect to 2 separate plugs on the back of the connector; one black and the other white for the seat base and back. Remember, the supply side can only be tested with the ignition on (circuit 15R)- I think!
As for the SRS warning light, it happened to me. I had to visit a dealer to reset the light. It seems to me that the SRS is always 'ON' and any loss of power during plug disconnection is recorded as failure by the system. Your dealer could be using a different technique or he simply resets the SRS light afterwards. Do you want to try pulling out the yellow plug and observing what happens?
In case you need to remove the seat, here are some useful instructions from SLK world. He also talks of the SRS warning light avoidance procedure.
I'm not going to mess with any SRS stuff, unless I have to!
Those three plugs in the picture... My setup is just a little bit different (and it's the passenger side if that matters). Meaning, the way the large, black, plastic "contraption" secures to the metal framework is slightly different. But I was able to easily remove it from the metal framework and turn it around so I could pin the back side of both the black and white connectors (with the supply-side connector removed, of course). I didn't remove the black/white connectors as I didn't think it would matter. Both connectors ended up settling in around 14 Ohms (NOT "K" ohms... single ohms). They both started at 3 Ohms, but climbed to 14 over about 3 seconds. It's 35*F right now, maybe that has something to do with it?
I don't think I can test for Volts on the supply side connector since the button lights won't stay on?
On a side/interesting note. I don't have underseat lights, but do have the connector/wires on the backside - just no supply side.
I think 1 represents a broken circuit. Your figures are in the ok range. Try continuity testing, if your multi-meter has that option. It should beep if there is a continuous circuit.
When I measured the 14 Ohms, that's the same idea as doing a "beeping" continuity test. It is just telling me the actual value. 14 Ohms is very low resistance, which shows good continuity. Some meters show a broken circuit as a "OL" (Over the Limit"), some show a "1.", some show the Infinity sign (sort of a sideways 8). Either way, it's just different ways to do/show the same thing.
There’s a class action and a pending recall from MB on seat heater elements on M,GL and R class cars from 05-10. I got my letter this week and there are three options: ignore, have repair done partially at MB’s cost or sue.
There’s a class action and a pending recall from MB on seat heater elements on M,GL and R class cars from 05-10. I got my letter this week and there are three options: ignore, have repair done partially at MB’s cost or sue.
Max, are you saying my problem might be a bad element? Correct me if I'm wrong, but didn't I eliminate the element as a possible culprit from my testing?
The class action suit (and secret settlement) only concerns a potential 'hot spot' which has occurred in a particular spot on some of the production units. The fix is to jumper wire around that spot.
If the Settlement becomes effective and you remain a Settlement Class Member, you will not need to do anything to become eligible to receive covered future repairs at authorized Mercedes-Benz dealers.
If the Settlement becomes effective and you remain a Settlement Class Member, and you want to receive the Bypass Wire Repair Procedure, you need to submit a Bypass Wire Repair Claim Form Notice by January 12, 2018.
If the Settlement becomes effective and you remain a Settlement Class Member, and you want to get reimbursed for costs paid to repair a seat heater in your Subject Vehicle(s), you need to submit the Reimbursement Claim Form by January 12, 2018.
Assuming that this isn't the exact problem that I'm having... but, that aside, if I have not received a letter, which I suppose is possible since I'm not the original owner... should I call my local dealer with my VIN to see if my car is affected? Is that the proper way to do it?
Alex, if you happen to still be monitoring this thread... Is there anything else I can easily check at home? Or does it need to go to a dealer to be checked with STAR/DAS?
So... FINALLY got around to doing this 1-minute voltage check/followup 😏 I stuck the DMM probes into the supply side connection without removing any connectors as it was easy to get to. While looking at the meter, I pushed the seat heater button and was able to observe the display quickly change, indicating a quick burst of 12V. The button lights only stay lit for about a half second so it's not enough time to get a stable reading.
11-14-2017, 12:13 PM
