R129.058 with M104 - MAS plug pin outs - PeachParts Mercedes-Benz Forum

waynesb · #1 09-15-2007, 05:03 AM

Hi

Because my harness to the MAS connector has disintegrated I was going to rewire from the firewall to the MAS connector plug, (the worst affected bit. It sits above the exhaust).

I was going to replace the whole engine harness but the one in my engine bay looks OK, (maybe it's all ready been replaced), AND the MAS harness is NOT part of the engine harness.

Can anyone with a wiring diagram tell me what I should expect on each pin of the plug that connects directly to the MAS? Even more helpful would be the colour chart, (i.e. green wire with brown strip connects to pin x)...

The connector has 5 pins but only 1,2,4&5 are in use. I'd assume there's a ground and 12 V and a couple of others?

Anyway I know it's a bit specific but...

OR is the wiring diagram for a R129 on-line somewhere? That'd be WAY cool.

Thanks

Wayne

waynesb · #2 09-16-2007, 01:45 AM

Yes, apparently there is tech info online at Startekinfo however apparently my NZ credit card doesn't support address verification, (which is just as well as startekinfo doesn't cater for states etc outside of the US, so I had to say I lived in Hawaii! ;-)

Thwarted at every front. Guess I should have perservered in trying to separate all the corroded wires to check the pin outs before I chopped open the plug to rewire it...

I'd still really appreciate a pin out or an explanation of the wiring at the other end of the harness to get me out of this mess...

W

SL280 - R129.058 - Beginning to shake my confidence ;-)

waynesb · #3 09-16-2007, 04:21 AM

Well at least Alldata will take my credit card, although I had to say my car was a SL320 rather than an SL280. I doubt the wiring diagrams are too different, (if you know they are please SHOUT).

I think I'll be able to use the data to sort out my repair... I'll let you know, (not that anybody is listening

), just in case you're in the same bind.

W

waynesb · #4 09-20-2007, 05:14 AM

The wiring diagrams from ALLDATADIY do in fact have the wiring colours, (in tiny little writing), so that was a BIG help. It seems that all my problems were due to the wiring to the MAS shorting out, as it is now running sweet as!

SO I ran a new home made heat shrink covered harness, (it's only four wires), back to where the MAS wiring disappears beneath the brake booster into another very major harness coming from, (or going to?), the fuse box.

On one of these MB forums I saw an example of someone who had cut a plug open to replace the wiring inside and I used that as a model for my repair. I had to use a a razor and a hammer to gently prize open the molded plug. Downside is that the epoxy I used to close it all up isn't hardening very fast, (it's been 24 hours), so I have braced it and hope the heat above the exhaust helps the epoxy to harden otherwise I'll have to come up with plan b...

I can see why they didn't replace the MAS wiring when they did the rest of the engine bay harness, and I can see why MB changed the later MAS wiring to go across the engine bay. I slid heat shrink as far back over the original wires that I connected my new harness to. The wires that far from the engine bay looked like they were in pretty good shape anyway, but I won't be putting any money on them not playing up in years to come...

Regards

Wayne

tecqboy · #5 09-20-2007, 11:30 AM

Thanks for the write-up. I believe a lot of us follow these threads, but have nothing to contribute, so we keep quiet. I do not have a wiring diagram for my vehicle either. I would love a large "paper" copy.

waynesb · #6 09-21-2007, 12:47 AM

Well if you've got a '94 SL320, I have a deal for you!

I think it's the same for an SL280 but I make no guarantees...

I've made up one big jpg of the engine bay wiring diagram for a '94 SL320. You can print it out on A3 to have a big diagram but I found I could read it on A4. If you want it just email me...

waynesb · #7 09-21-2007, 12:54 AM

I should also say that today was the first time out in the sun with the top down in the SL. A couple of work mates and I went for a lunch time jaunt, it was great. The workmate who drove today also drove it the first day I owned the car, (he helped me pick it up three weeks ago), and was impressed with the improvement.

It was nice to be out in the car and not worried about whether it was going to cough and stall etc etc

I volunteered to sit sideways in the back as I'm a short a*se and was the only one who'd fit!

Spring is here and I can feel a nice summer ahead...