Swap 87 300TD interior with 93 300TE - PeachParts Mercedes-Benz Forum

homepagz · #1 12-28-2012, 09:06 AM

I think I understand the level of effort it will take to swap a complete - color changing - interior...

But will the interior pieces/parts swap cleanly (without modifications) from an '93 300TE to a '87 300TD?

If this is a stupid idea - please just say so.

Thanks,

-John

ds190 · #2 12-28-2012, 09:29 AM

It's a great idea, and has been done before by many people.

The main issue will be the power seat controls- if one set has memory and the other does not.

vstech · #3 12-28-2012, 09:35 AM

also keep in mind that with a color change, the dash board will have the original color for a lower base.
it's not terribly difficult to remove the dash, but keep that in mind.

jay_bob · #4 12-28-2012, 12:12 PM

They changed the power seat controls between 87 and 93.

The 87 power seat controls have individual wires for every function (i.e. one pair of wires for cushion back and forth, another pair for headrest up/down, etc.) while the 93 went to a data bus system between the seat switch and control box.

As long as you are swapping the entire interior to include the seats you should be fine. Just be sure to grab the wire pack between the seat control switch in the door and the under seat electronics box on both sides from the donor car.

Ref. 124 FSM 82-0860 for the seat control system.

If you don't have it already, go to w124-zone.com and register, they have a complete set of the 124 FSM and a cleaner copy of the ETM than is available at startek. You will definitely want both to see how things go together.

Oh and one other thing, the tach from a gas will definitely not work on a Diesel. If you decide to swap the whole cluster keep that in mind. The fuel/oil/temp gauge will work (but it says unleaded only, you might want to blank that out) but the tach is a definite no go. The speedometer will interchange, as the rear ends are the same ratio between gas and Diesel wagons.

Dash is not terribly hard to pull. Worst part is removing the steering wheel. The FSM procedure is straightforward and easy to follow. Important safety tips:
- Be sure to disconnect the batttery and then the red maintenance plug below the passengers feet before doing anything to the steering wheel (or the seat belt tensioners).
- When undoing the big allen bolt behind the steering wheel do not use the column lock for a counter hold. Have the key in the switch and have a friend hold back on the wheel while you use the longest cheater bar you can find.

The 93 will have passenger air bag and the 87 does not.
I believe you can swap the cross bar behind the dash as they changed it to accommodate the passenger air bag.
You will have to swap the air bag control module, the 87 will only have outputs for the driver and belt tensioners, you need the 93's controller that has the extra outputs for the two pyros on the passenger bag. Be sure to grab the entire air bag wiring system from the donor, and note they changed the backup power supply system as well. This is located in the passenger foot well.

I would also swap the transmission shift interlock assembly from the 93, that is an important safety feature. This is cable interlocked between the ignition switch, the brake pedal, and the gear selector.

TheDon · #5 12-28-2012, 12:28 PM

One cannot just change the wire ends to match that of the old plug style? I have a seat back from a 93 I want to put into my 87 I was just going to change the wires for the motors to that of the old style

vstech · #6 12-28-2012, 12:38 PM

the motors and seats are the same, but the controller and function from switch to seat is different. you can change the seats themselves between the systems. you do have to hack into the wiring inside the seat though.
thayer has a writeup on here about it.

homepagz · #7 01-02-2013, 03:55 PM

As jay_bob mentioned - the driver seat wiring harness if very different between the '87 300TD and the '93 parts car.

I will be pulling the wiring harness out of the '93 as well as the door switch.

Only question I have is - how do I integrate the new wiring harness into the car's power/etc?

Thanks,

-John

jay_bob · #8 01-02-2013, 04:28 PM

On the 87 the memory box gets power from X30 under the driver foot rest just for constant power to save the settings. The motor power comes from the two auxiliary 25 A fuses under the relay cover.

On the 93 it looks like they upgraded the memory controller so that it did not need the separate backup power - there is a reference to this in the FSM that they changed the memory circuit so that it did not lose the settings when the power was disconnected. The 93 just has the two 25 A feeds from the relay box.

I would say that there should be no reason to cut any wires when doing this swap. If you find that something needs to be cut I would think twice. Remember that the connectors can be opened (with very few exceptions) and the pins can be removed and even resoldered if necessary.

I would highly recommend getting access to the online FSM and ETM and have it handy on a computer in your work space. You can register at w124-zone.com and have access to the same info as on startekinfo.com but with a better HTML interface. Also they somehow got hold of a cleaner copy of ETM than the one available directly from M-B.

I would also make use of the EPC, that will help you see how things fit together. And I would be lost working in the garage without being able to listen to Pandora or iheart radio.

. So a computer in the garage is an invaluable tool...

I am an electrical engineer, I play with control systems, so issues like this are what I live for at work. If you get stuck on something let me know.

homepagz · #9 01-02-2013, 05:22 PM

Great info! Thank you!

The '87 *DOES* have the two memory seat option - and the '93 *DOES NOT* have the memory option.

Do you think this will be an issue? I was thinking as long as I have the harness and the door switch from the '93 it shouldn't be an issue.

-John

babymog · #10 01-02-2013, 08:33 PM

Just remove the motor pack from the bottom of the '87 seat and put it on the new seats. The seat will need to be moved rearward to access the two front bolts, four bolts hold the power base to the seat. 15 minutes including taking a photo and unplugging the wires, plugging into the original base.

There is no reason to remove the steering wheel unless you're installing the later leather wheel, extend it to make it easy and the dash comes right around the steering column.

I have a '93-'95 interior in my '87, very much like it (couldn't go backward after having the newer cars). The driver's door steel will need a little nibbling to fit the speakers, otherwise very straightforward. The original glovebox and frame will need to be swapped onto the new dash if you want a glovebox, and you might need to spray the lower dash if you can't find the right color, what colors are you changing from/to?

homepagz · #11 01-02-2013, 09:04 PM

Babymog,

Yes! I had thought of taking the seat bottoms off - just as you described. I had found this in one of the forums.

I had started this and had the seat bottoms almost off when I noticed that the wiring that feeds up INTO the seats connected to the seat bottoms differently between the two.

I stopped when I didn't see how to correctly rewire the seat tops (and their associated wires) with the swapped seat bottom.

I'm all for this approach - am I missing something?

Thanks,

-John

babymog · #12 01-02-2013, 09:28 PM

I believe that the connectors are all the same, I'd have to search back about a year to find the posts where we described it though, ... one other poster did it the same time I did. I think that it was maybe a different connector housing?

Is one of the seats heated? That will have additional wires. Memory isn't helping me here.

The passenger side seat bases should be the same.

homepagz · #13 01-02-2013, 09:34 PM

Correct - the passager seats are drop and play - no issues there.

Maybe the issue I'm dealing with is that the '87 seat bottom is wired for 2 position memory and the '93 seat top is wired for no position memory.

I'll look again - but I'm 99% sure that the wiring connectors coming from the seat itself down into the base is different between the two.

-John

jay_bob · #14 01-02-2013, 09:52 PM

The memory seat motors will have position transducers (just a simple potentiometer) on them, hence the extra wires.

Just a thought, could you keep the 87 seat frames and motors and controls and swap the skins?

homepagz · #15 01-02-2013, 10:09 PM

Haven't looked into swapping the skins.

I'll have to look into that. Disappointed that the seat swap is such an issue.

-John