87 and 94 w124 SWAP - Page 2 - PeachParts Mercedes-Benz Forum

Jeremy5848 · #16 09-29-2008, 11:37 AM

Quote:

Originally Posted by 300DTurboW124

. . . the electric seats only work when the door is open . . .

These cars have two circuits that both operate the power seats. The first is activated by one of the front door relays and allows you to adjust the seat before you get into the car. This is working in your car, based on what you say.

The second circuit is the "normal" circuit, which is powered through the ignition switch, Fuse 2 (16 Amps, in the main fuse box), and V1, the "power seat diode," which is also in the relay area behind the main fuse box. V1 is all the way to the back, next to the firewall, and on the left (driver) side of the relay box.

The fact that the power seats work at all means that K5, the power seat relay, is good, as are fuses "E" and "F," which are in an "auxiliary fuse holder," located in the relay area behind the main fuse box (remove six captive screws to get the cover off). The aux fuse holder is in the right (passenger) side of the relay box, all the way to the front of the relay box, and holds only two fuses (25 Amps).

The culprit, however, is most likely to be Fuse F2 or V1, the "power seat diode." Fuse F2 also powers the wiper/washer circuit and the power window circuit so you can easily find out if it's bad. If it is good, check V1.

You can check V1, the "power seat diode," by pulling it out of its socket in the relay box and using an ohmmeter. With the ohmmeter leads connected one way, you should get continuity through the diode. With the leads reversed, you should get no continuity. No continuity either way means the diode is "open" and that is the source of your problem. Continuity both ways means a shorted diode; in that case, the seats would work but the windows and wipers would also work with the doors open and you can check for that.

If the diode seems to be good but the seats still don't work with the doors closed and key on, you may have a broken wire someplace and that will be much harder to track down.

Let us know what you find.

Jeremy

300DTurboW124 · #17 09-30-2008, 03:43 AM

Quote:

Originally Posted by Jeremy5848

These cars have two circuits that both operate the power seats. The first is activated by one of the front door relays and allows you to adjust the seat before you get into the car. This is working in your car, based on what you say.

The second circuit is the "normal" circuit, which is powered through the ignition switch, Fuse 2 (16 Amps, in the main fuse box), and V1, the "power seat diode," which is also in the relay area behind the main fuse box. V1 is all the way to the back, next to the firewall, and on the left (driver) side of the relay box.

The fact that the power seats work at all means that K5, the power seat relay, is good, as are fuses "E" and "F," which are in an "auxiliary fuse holder," located in the relay area behind the main fuse box (remove six captive screws to get the cover off). The aux fuse holder is in the right (passenger) side of the relay box, all the way to the front of the relay box, and holds only two fuses (25 Amps).

The culprit, however, is most likely to be Fuse F2 or V1, the "power seat diode." Fuse F2 also powers the wiper/washer circuit and the power window circuit so you can easily find out if it's bad. If it is good, check V1.

You can check V1, the "power seat diode," by pulling it out of its socket in the relay box and using an ohmmeter. With the ohmmeter leads connected one way, you should get continuity through the diode. With the leads reversed, you should get no continuity. No continuity either way means the diode is "open" and that is the source of your problem. Continuity both ways means a shorted diode; in that case, the seats would work but the windows and wipers would also work with the doors open and you can check for that.

If the diode seems to be good but the seats still don't work with the doors closed and key on, you may have a broken wire someplace and that will be much harder to track down.

Let us know what you find.

Jeremy

thats the symptom my dad's 87 is doing... im hopin the 93 isnt the same problem.. i still havent gotten it yet... hopefully by wednesday\thursday ( waiting for title) i should have it here...

this is how my 87 looks like ...

300DTurboW124 · #18 10-17-2008, 03:03 AM

alrite i got it finnnaly here... posting pics 2morrow ... can anyone please tell me if 86 thru 93 have the same front ... like rad support , radiator , hood, fenders, ..

babymog · #19 10-17-2008, 12:23 PM

Radiator different I believe, fans different, hood same, fenders different ('90s has vent on RT fender, can be used on '87), lights same, grille same.

300DTurboW124 · #20 10-17-2008, 05:01 PM

here are the pics... tell me what you guys think

Bio300TDTdriver · #21 10-17-2008, 11:32 PM

I think both airbags worked.