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Ron Stygar Carl Buckland Dale Beuning Forums Help
From digest.v5.n452 Sat Oct 26 15:39:18 1996 I took the plunge this weekend and attempted (successfully, I might add) to repair a malfunctioning drivers side seat heater in my 1992 325i. Hopefully this is not a big WOB. Let me know what you think. For those of you who are interested here's the gory details...
Tools required: Digital Multimeter (only cause I have one),
needle nose pliers, Parts required: Cushion Clip (# 52-10-8-130-678) $.88 each 4 required Seat heater element (part number ?) $90.00 (hopefully you
will not need one of
these)
Background: My drivers side seat heater has been inoperative for several months. The last repair was performed by the dealer under warranty to the passenger side over a year ago. Both of these heating elements are on the lower cushion (not the ones on the backrest). The dealer says that you cannot repair the seat heating elements since they are made with very thin wires. It takes several hours of labor. They said they tried to resolder them on other cars but always failed. BTW my seats are manually adjustable leather sport seats
Detailed Instructions: Disconnect Seat heater cable connector - Tilt the entire seat assembly back so that the front is up and pointed toward the roof. Under the seat frame and toward the back you will see 3 connectors. They are attached to each other by clips and can be slid apart. Disconnect all three of the connectors. Don't worry about reconnecting them as there is only one way to stick them back together Two of the connectors are for the upper and lower seat heaters, the third is probably for the seat belt connection circuit (warning chime). Remove seat from car - Take the seat out (if you have a 4 door remove it from the rear door). Don't worry about the seat belt tensioner just leave it connected and pull out enough seat belt to allow the seat to rest on the floor of your garage. You don't really have to remove the seat if you are familiar with the workings and positions of the stuff under the seat frame. In my case I needed to have a better look, and also it made it easier to explore the parts PRIOR to disassembling them (plus I wanted to clean out the thousands of dollars in pennies that I expected to be wedged down in the seat tracks). Next time around I think I can reach under the seat and disconnect the element connector without removing the entire set from the car. Test system function - You can use your multimeter to verify that voltage is making it to the element connector (on the car side). You can also test the element connector (on the element side) to verify continuity and resistance. Infinite resistance on the seat side means the heater element has a broken wire. If the heater element is the problem then continue with these instructions. If the car is the problem, then you are entering the twilight zone - good luck. Remove Lower seat cushion - Just yank hard on each of the four corners of the seat cushion. This will force the cushion clips to break in half and release the cushion from the seat frame. The clips are designed to break (that's why you need 4 replacement clips). A portion of the clip will probably remain in the seat frame holes. Use a punch and a hammer to drive them through and clear the holes in the frame. The lower seat heater cable should be fished through the square hole in the back of the lower seat frame, then you can remove the cushion completely from the seat. You are now ready to really get into the hardest part of the repair. Remove seat cushion cover (leather in my case) - With the seat cushion completely disconnected from the seat assembly and the car, you can remove the leather cover. The cover is attached to two things, the seat cushion frame and also the seat cushion foam. The seat cushion foam is molded directly to the lower seat frame - you cannot separate the two pieces, they are one part. The seat cover is stretched over both and held on by hooking many little holes over a bunch of small plastic pins. Remove the leather cover by pulling on the cover and un hooking the hole from the pin. Do this around the entire outside of the leather cover. The Leather cover has now been detached form the seat frame. To detach the leather cover from the seat cushion, you must pull on the cover to reveal the small round "hog rings" that are used to hold the wires of the cover to the integral wires of the seat cushion. There are 16 hog rings used to hold on the leather cover. 3 along each side and then 3 sets of 3 rings along the inside panel. I used a pair of needle nose pliers to stretch the hog rings apart enough to release the wires. Once all the hog rings are pried apart you can work the wires loose and completely remove the seat cushion leather cover. Locate damaged area in seat heater element - This was very easy for me to spot. The wire was burned through. It appears the heating element is manufactured from some kind of flame resistant fabric. The element wire is threaded through the fabric. You will need to use a sharp tool to pry apart the fabric fibers and reveal the wire. My damage are showed up as a little brown char both on the fabric insulator cover and the seat cushion foam. Repair damaged area (tricky part) - Try and pull enough of the element wire out from both ends. Strip enough insulation off the wire so that it can be twisted back together to restore the electrical connection. Then wrap it tightly with insulated electrical tape . You might try high temp shrink wrap insulator of you have some available (the kind you heat up with a hot air gun). Once the wire is fixed then tuck it back in the insulated fabric being careful not to overlap the wires. USE YOUR MULTIMETER TO CHECK YOUR WORK NOW. If it turns out you cannot or choose not to repair the original element NOW is the time to install a new element ($90). Reinstall element - Place the new or repaired element back on the seat cushion foam. Make sure it is positioned in the same way you found it during disassembly. Reinstall cushion cover - Reverse the hog ring adventure. Use a pair of pliers to recompress the hog rings around the wires. This will take a while and some patience. Your attempt will probably be just as frustrating as the tech at the dealers would so don't get to upset. Think of how much money you are saving ($60- 70 per hour ?)... Smile to yourself, and take a break if you get upset. Once all the hog rings are re compressed, you can pull the cover over the cushion and pop the little holes over the plastic pins. Reinstall Seat cushion Now you have the seat cushion reassembled. Go get the replacement seat cushion clips (qty 4). Inset one clip into the bottom of the seat cushion (not the seat frame). The triangular end it the part the pushes up into the seat cushion. The plastic frame, which in integral to the cushion foam, is more pliable than the plastic clip. The clip will force fit into the hole. After pooping in the 4 new clips then position the seat cushion on the seat frame and pop each clip into the corresponding hole in the frame. You will have to push hard. Make sure the seat heater connector wire is correctly threaded through the square hole in the back before popping in the clips. Reconnect the three "seat side" connectors so they are attached to the lower seat frame. Clean the area under the seat (might as well while you are in there...) - Self explanatory. I used carpet shampoo. Place seat back in car - Place the seat exactly over the studs in the front, then tilt the seat back so the frame is at an angle just like you did when disconnecting the connectors. Reconnect all seat cable connectors) - You can make a mistake here cause both the upper and lower element connectors are the same and it doesn't matter which one you hook to the other. The third connector can only hook to the identical connector on the seat. Test system function - Start car - attach seat belt - test seat heater. Of everything is OK then proceed. If not, go back to beginning. Be sure to check the fuse, check the connectors under the seat, etc. Reinstall the seat - Install bolts and nuts - torque as spec. Test system function - Go drive on a cold day with the windows down with a warm seat.
Hope this helps anyone out there with a similar problem. Additional comments are greatly appreciated !
joe. |
