I had a rip in my driver's seat repaired. The material repair was good, but after I reinstalled the seat the seat heater did not work. I took pictures of the electrical connectors before I removed the seat, so I'm sure I reinstalled them correctly. (They only go in one way.) I did find that some of the wires on the seat were wrapped in electrical tape. (These are under the seat bottom where the wires enter the seat.) I removed the tape and found that the wires had been cut and taped back together. I called the upholsterer and he admitted that he had cut the wires in the process of separating the two parts of the seat. He said he only cut those two wires, but I suspect that he had to cut others inside the seat.



Wires wrapped in electrical tape


Cut wires

I soldered the wires and used shrink tubes to protect the soldered portion of the wire. Unfortunately, that did not fix the problem. I also checked the fuses(#25 and #41) based on the assumption that the poorly-repaired wires had shorted, but the fuses were fine. The controls for the seat motors work fine and the passenger seat heater also works.

Here are my questions:

1. Does anyone have any suggestions for how to access other wires that may have been damaged in the repair process? I'm wondering whether I can remove the trim on the side of the seat to see what is going on.

2. Are there any other components (such as a relay) that could have been damaged by a short?

3. Could the upholsterer have damaged the seat heater grids when stitching the new panel to the cover?

I can always remove the seat and take it back to the upholsterer and tell him to fix it, but I don't have any faith in the guy right now and if I can fix it myself I will avoid wasting a lot of time.

 

Why are we hearing this story----you should be running back to the idiot that caused the problem and have them fix it!

 

Thanks for your feedback, and I suspect that may be the solution. I wanted to explore the option of fixing it myself and avoid the inconvenience of either removing the seat and dropping it off or leaving the car with the shop and catching a ride with someone.

Also, while I am annoyed with the upholsterer, I find it more productive to treat people as intelligent individuals and provide specific guidance on how I want them to correct a mistake. For example I would prefer to say, "Wires a and b between the seat back and the seat bottom need to be soldered together," than "You are an idiot, fix this."

 

This is just shooting in the dark (and possibly with blanks) ...
If you have access to an electrical meter (VOM, as in volt, ohm, multimeter) you may want to see if there is a complete open (infinite ohms). when checking the wires to the seat. I would expect there to be some level of resistance, but not complete open. However, can't say for certain that is the case, but would be a clue. If you get some type of resistance reading, then there are next steps. If it is a totally open circuit, then your option is to go back to the upholsterer and work a deal for them to fix this,.

Another test with the VOM, would be to measure the voltage present at the connector to the seat when the heater switch is on. I think you should see between 12 and 14 volts (again just speaking from general experience). If you don't see anything (as in less than 1 volt), it could it be the connector got damaged.

Getting the wires soldered together and wrapped with electrical tape is also a must if it looks like the connector is okay (you have power when the switch is on) and there is a level of resistance reading for the seat.

Most of all good luck! Heated seats are practically a mandated option here in Minnesota.

Regards,
Bruce

 

Thanks

I have a multimeter and I was planning to check for continuity this weekend when I have some time. I hadn't thought of checking the voltage, but I will add it to my list.

It is not a cold in Virginia as it is in Minnesota, but I've become accustomed to seat heaters in my other cars and I will need to keep after this until I come up with a fix. I think a trip back to the upholsterer is likely, but I'd like to provide specific guidance to him on the repair.

 

Any update? Could the seat heater control module have shorted out when the wires were cut?

https://www.ebay.com/itm/Mercedes-Be...1VzgjI&vxp=mtr

 

Thanks for the suggestion. I'm still in the brainstorming phase on this problem and I'm considering all possible causes. I took the seat out of the car and brought to the upholstery shop, so I don't think that is the cause. Maybe when I was doing my repair something happened. However, I'm pretty sure I had disconnected the seat wiring in order to tilt the seat back for access to the cut wires.

I'm going to have some time tonight or tomorrow and I plan to follow bjbina's suggestion and check for continuity.

I think there is a poor connection somewhere.

 

I used a multi meter to check the continuity in the seat heater circuit within the seat. The meter read 1. I checked the circuit in the passenger seat (which works) and the reading was just above 0. (So there must be a break in the circuit somewhere inside the seat. I partially disassembled the seat in the hope that I could find the problem and save the inconvenience of bring the seat back to the shop, but I couldn't find any obvious problem.

So, I'll be bringing the seat back as soon as I can.

 

I finally sorted out the problem. I brought the seat back and the installer took it apart. He told me he "must have sewn through the seat heater elements." He agreed to install a new seat heating pad and I attached the wires to the existing ones in the seat harness. The Dorman model 628-040 Universal seat heater is the model he used. He only used one of the two pads in the kit, so I have the second pad and the wiring harness that came in the kit if anyone needs it.