W202 Heated Seats Wiring Information

[Andy_C]

I am trying to wire up the heated seats in my 2000 W202. I have a set of switches and ( I think a) control unit , 210 820 0151, On the top left hand side of this unit is a plug with 4 connections. ( Marked 1, 2, 3, 4)
I beleive that connection 1 supplies power to one of the seats. I think that connection 3 supplies power to the other seat.
However, I don't know what connections 2 and 4 are for. I'm guessing that connection 4 is power input as it is a fairly thick wire ( red with a yellow stripe), but I'm really not sure what connection 2 does. It a fairly small diameter wire ( smaller than the other three). It is pink with green hoops and a yellow stripe. I don't want to apply power to the unit without knowing what the inputs should be and what the outputs are.

Can anybody please tell me what the wiring should be or direct me to a free resource that will tell me.

Thanks in advance,
Andy

 

[Mercedes cozy]

I believe the yellow and red is power, either constant or ignition positive.
Do you not have any brown wires as they may be earth negative.

Can you post a picture.

I am trying to wire up the heated seats in my 2000 W202. I have a set of switches and ( I think a) control unit , 210 820 0151, On the top left hand side of this unit is a plug with 4 connections. ( Marked 1, 2, 3, 4)
I beleive that connection 1 supplies power to one of the seats. I think that connection 3 supplies power to the other seat.
However, I don't know what connections 2 and 4 are for. I'm guessing that connection 4 is power input as it is a fairly thick wire ( red with a yellow stripe), but I'm really not sure what connection 2 does. It a fairly small diameter wire ( smaller than the other three). It is pink with green hoops and a yellow stripe. I don't want to apply power to the unit without knowing what the inputs should be and what the outputs are.

Can anybody please tell me what the wiring should be or direct me to a free resource that will tell me.

Thanks in advance,
Andy

 

[Andy_C]

Hi,

Attached photo shows the unit.
The brown wires are in the plugs that fit to the seat bases. I'm assuming that since a heater element is only a resistance that each brown wire should be earthed.
The other part of the plug that fits into the seat has a wire that corresponds in colour with connection one and three in the inital description and photo.

Thanks,
Andy

 

[Mercedes cozy]

I'm not sure if i'm right but I believe there must be a relay that fits in between the switch and the seats.

 

[mr. shr]

PM me your email address.
I have a drawing that *might* help you.

 

[andy27168]

Hi,
I think you also need a control unit, which switches the double element heating to the single element heating after 5 minutes or so, the unit you have is just the dash switches, why don,t you buy the genuine MB loom then all the cables will have the correct connectors fitted, plugged up correctly an be the right length and from the diagram below you could almost predict where the cabling goes, there may even be a correct paper in the WIS to give you exact instructions to install it, the correct loom for your car i believe is the pt no ending in 1108 and is only £23.43 as the second link i,ve posted shows.
If you want i,ll have a look on the WIS for you.

Êàòàëîã

CABLE HARNESS - - Mercedes-Benz Parts, Inchcape

 

[Andy_C]

Hi Andy 27168,

I think thats whats shown in the phot is a control unit. It may not be as the link ( ie/ the correct one for a W202) but I think it should do the job ( if thats what it is). If it's just a set of switches I should be able to measure continuity across the switches when one or other is pressed. I can't do this, instead getting a reading of several megaohms whether the switch is made or not. I've tried opening the unit (to no avail, I'm too afraid of breaking it) and from what little I can see it's not just wires running to the switches inside.
One of the reasons for not buying the loom is that item 75 in the link is £115! ( + vat). I'd then need to buy the switches separately and the loom, and I'm on a tight budget ( spent it all on the electric seats).

If you could have a look on the WIS I'd be very appreciative.

Thanks,
Andy C

 

[andy27168]

Are those switches from a 202? don,t take to much notice of the diagram as the EPC diagrams can be inaccurate, the switches if i recall correctly on that part of the dash come off in one unit and what you have are just two separate switches on the dash switch carrier.
I understand that you are on a budget but if it was me i would still be going for the OEM solution as there could be some possible safety issues, seats melting etc, look for a second hand unit, by the time you have wired in relays etc its got to be a lot less hassle.
I have located the wirng drawing for the heated seats and a set of retro fit instructions from the WIS, i,ve sent you a PM
Good luck bud.

 

[NW_Merc]

What is the part number for a wiring loom for heated seats for a pre-facelift W202 with the square switches?

 

[andy27168]

look at my link from the russian site it lists 2 cable harnesses (item 15), the one ending in 1108 is for a facelift, the other is for the pre facelift, though very early C classes had the heated switches in a different place, (on the gear shift panel) this "should,nt" make a difference to the loom if you wanted to fit them in the later place as the loom would be long enough just routed slightly i believe.

 

[NW_Merc]

Of course, the facelift loom could be modified by attaching the correct plug to it if it works out too expensive for the pre-facelift? Or is this not a good idea?

 

[andy27168]

I personnaly would still use the pre face lift loom, and "IF" nessacary extend the switch leads.
Do please get the loom number checked before ordering, but i hate to say this in my experience any pre-face lift loom i have tried to order has been obsolete or not made anymore so you may have to modify a later loom.
If you drop me a PM with your e-mail I,ll mail you some info, wiring drawings, retro fit instructions (from the WIS) and another circuit diagram i have for the heated seats.

 

[ypkx]

Hey,
can someone tell me if there's like a generic wiring/loom kit i can probably purchase from mercedes or something to wire my heated seats to the console?

edit- nevermind, just read andy27168's link and it still workS!

 

[ypkx]

update, just spoke to the mercedes garage, and was told that i would need a complete different seating wiring which i can understand.
My car is a P reg 202 Classic 1997 model. The seats I believe are from a 1999 or 2000 model, but I will need to confirm these from Z4hid. I have the control unit, and the seat but need the kit to wire from fuse to the buttons and seats ive been told.. quoted £179 + vat.

 

[NW_Merc]

I have that loom and that's how much I bought it for..... it's brand new, never been fitted and I can give it to you for what I bought it for if you want it. PM me if you're interested.