[SawyerF]

So... this is my first post on this forum, although circumstances are rather unfortunate. I have a 2010 bmw 335d with idrive and about 3 months ago I ran into an electrical issue while driving, all of the electronics went haywire while I was driving, service now, gauges cycling, etc., and smoke came out of the center of the dash through the air vent. Now being a "YouTube certified" mechanic I took it to bmw of fort Walton to see what they say about it before I spend >$1500 to get it fixed. They were able to tell me that one wire had voltage when it was supposed to be flat. They said it would take them 10+ hours just to get the dash out so I decided my time cost less than theirs and towed it home. I managed to get the dash, knee bar and hvac system out fairly easily. Now I'm staring at about a million wires wondering where to start. From what the bmw techs said I should be looking for two wires that shorted together right? Even when I do find it how will I know all my control modules didn't get shorted as well? I'm not exactly sure where to start on this and there is nothing online ( that I can find) that points me to the right direction. Visually the wires look clean, bundled, and dry. I'm 19 and doing this by myself, I believe this is where experience comes in handy.[IMG][/IMG]

[Canadiesel]

I do not envy your position. I know it sounds dumb but could you do a smell test to at least narrow down the area that is burnt/shorted?

[PerfectAce]

Shot in the dark, but take a look at the blower motor wiring. It's been known to short/melt/catch fire. There's actually a open recall for the e90 regarding this issue.

I'm not sure how a shorted blower motor harness would lead to your other faults, but the fact that you reported smoke coming out your vents would lead me to start looking there.

[PerfectAce]

I'm looking at your pics a little closer, and the control unit box concerns me. Like, what in the hell is going on in there? Somebody correct me if I'm wrong, but those crimped butt connections are not factory. Exposed wires just twisted together? Cut wire with what appears to be an electrical tape tag hanging off the end?

And most revealing, the soot on the underside of the box lid. That doesn't look to be your normal dirty diesel soot that finds it's way into nooks and crannies under the hood. That looks to be soot from the magic smoke of an electrical short.

The control unit box is your crime scene. Start investigating there.

[SawyerF]

Originally Posted by PerfectAce

I'm looking at your pics a little closer, and the control unit box concerns me. Like, what in the hell is going on in there? Somebody correct me if I'm wrong, but those crimped butt connections are not factory. Exposed wires just twisted together? Cut wire with what appears to be an electrical tape tag hanging off the end?

And most revealing, the soot on the underside of the box lid. That doesn't look to be your normal dirty diesel soot that finds it's way into nooks and crannies under the hood. That looks to be soot from the magic smoke of an electrical short.

The control unit box is your crime scene. Start investigating there.

PerfectAce the spot is from a melted exhaust back pressure sensor hardline i since fixed, as for the exposed/ cut wires i was thinking that may be from the dealership, the techs told me one wire has voltage when it shouldn't, he said he could label it for me but I was under the impression I picked it up (2 hours away) before he could. This electrical tape tag could be the problem wire but it still doesn't make sense to me why another wire would have voltage.

[SawyerF]

Originally Posted by PerfectAce

Shot in the dark, but take a look at the blower motor wiring. It's been known to short/melt/catch fire. There's actually a open recall for the e90 regarding this issue.

I'm not sure how a shorted blower motor harness would lead to your other faults, but the fact that you reported smoke coming out your vents would lead me to start looking there.

These are the wires to the blower motor, they look a little funky due to the waterproof glue but everything seems to be in tact

[PerfectAce]

Originally Posted by SawyerF

PerfectAce the spot is from a melted exhaust back pressure sensor hardline i since fixed

I had a feeling that your exhaust pressure sensor line had failed at one point. Have you given the wiring looms going into the control box a good look? They're obviously encased in the rubber conduit, but you might try pulling it away and having a look at the condition of the wiring inside. Specifically, the loom that runs through the forward-most conduit as that's the one closest to the failed exhaust pressure sensor line and was probably subjected to a great deal of heat at the time of failure.

[Jones68]

Looks like possibly someone tapped into some wires to run an amp/ subwoofer or something?

Is all that stuff still in tact?

[SawyerF]

Originally Posted by PerfectAce

I had a feeling that your exhaust pressure sensor line had failed at one point. Have you given the wiring looms going into the control box a good look? They're obviously encased in the rubber conduit, but you might try pulling it away and having a look at the condition of the wiring inside. Specifically, the loom that runs through the forward-most conduit as that's the one closest to the failed exhaust pressure sensor line and was probably subjected to a great deal of heat at the time of failure.

The looms coming out of the control unit box all seem to check out, I'm concerned about the butt connectors you said looked like they weren't stock. As far as I know the sound system in this car was not tinkered with. Let me know if these wires look correct. I don't have a wiring diagram and I feel a little blind to all these wires.

[Jones68]

That butt connector stuff is not stock.

Besides a stereo or alarm I can't imagine what is going on there
hmmmmmmmm

[Jones68]

Those orange stripe wires were cut and spliced into. Why I have no idea.

Maybe there is a wiring diagram out there that can give a clue as what was going on. Because yeah, your going to be blind without it....

Possibly someone was feeding a signal to bypass something. I mean I've seen that and done that 100 times on old muscle cars etc, but really strange to see on a "new" car.

Whatever that thicker orange wire is, they cut into it to put it to the smaller ones.

Personally since its a mess anyway, I'd take those apart, turn the key to accessory and see if that orange wire is 12V.

Can you see where everything should/could go back to stock? where did that thicker orange come from, where's the other end?

[robnitro]

Get a real scan of codes not P codes.
Carly or ista or this free https://play.google.com/store/apps/d....pw.btool.lite

[SawyerF]

Alright so I found the wire my short is in. I bought an online manual and looked at some of the wiring diagrams. Turns out I ripped everything out of my dash for nothing. The culprit was one of 8 red/ yellow wires in the e box, it threw a 20A fuse when they were all connected so the one that the BMW dealership marked for me had a short. I found out it leads to the swirl flap actuator and when I put a bi-pass wire in it didn't blow the fuse. Now I have to play the very expensive game of which control module did I short. I was also wondering if anyone knew what that plug coming out of the E-box is for (last picture)

[Jones68]

Well that sucks you pulled your whole dash out, but at least you found out where the issue is.
So that whole red/orange crazy splicing action has to do with the eFlaps? I'm not familiar enough with the engine yet to know why someone would do that.... maybe if someone can shed some light on that it will help.
Not sure what that other plug is....was it just unhooked?

[PerfectAce]

Originally Posted by SawyerF

I was also wondering if anyone knew what that plug coming out of the E-box is for (last picture)

Pretty sure that's your automatic air recirculation control sensor connector. It snakes along the leading edge of the lower part of the cabin air filter housing and plugs in to the sensor just to the inboard side of the control box cover.

[SawyerF]

Originally Posted by Jones68

Well that sucks you pulled your whole dash out, but at least you found out where the issue is.
So that whole red/orange crazy splicing action has to do with the eFlaps? I'm not familiar enough with the engine yet to know why someone would do that.... maybe if someone can shed some light on that it will help.
Not sure what that other plug is....was it just unhooked?

Yeah the bmw techs that I took it to tracked down that one wire out of the bundle then I guess they temporarily spliced them back together like that for some odd reason. I guess the next step is to find where that wire is shorted and make sure nothing else is shorted around it and run a new wire. It's been a slow process, working on it when I can but now I feel good about some solid evidence as to where the short is.

[SawyerF]

Ok fellas I need some help. I pulled out my engine harness and found what lies below, with seeing this I knew exactly what to do. I rewired all the burnt wires and tidied it up, threw it back in the car and when I tried to start it no luck. It wouldn't even turn over, although the idrive system came on and the gauge cluster works. I'm getting a transmission malfunction as well as a passenger restraint system error. I would like to know if I just need to clear the codes or reflash a ecu or tcu. If so how do I go about doing that

[ddinse]

Just a thought... a low battery will throw lots of codes. However a replacement harness may be in order

[BB_cuda]

OP, are 1st and 3rd picture from Post #17 the same area? The 3rd picture appears to be on the cooler driver side of engine bay. I would have expected to see burnt harness on passenger side from older threads but never seen damage like this on driver side.

My point of question is this. A local salvage yard has a 2010 335d that whole engine and transmission is taken from. I bought the ECU from same car. There is a decent chance the engine harness parts are still there. The car took a front end hit. I also bought the rear diff from it and it now has an LSD (Wavetrac) installed into it. I swapped and sold the original diff to a forum member. Let me know something.

Tell me which harnesses you need and I can check for you in next week or so. If under the dash, I'm not going to dig there. If under hood, I can try to help you.
EDIT: I just saw you are in Wichita Falls, TX. I'm on south side of Houston. I've driven though there 8 times on way back and forth to Colorado on 287.

[SawyerF]

The burnt section was on the passenger side from a hole in my exhaust back pressure sensor hardline (since fixed) I am looking for a new harness but parts 335d's are hard to find. I took my time when I rewired the harness so every wire has continuity and I had my battery load tested and charged before undergoing this. I'm hoping I just need to reset the ecu or something but I don't really know enough about bmw systems or what could be keeping my car from trying to start. One of my friends told me that the ecu may think the transmission is in gear and not allowing it to turn over. Just a thought but I'm not sure why it would think that

[BB_cuda]

PM answered.

[cm335d]

Where exactly on the passenger side did you find the burnt wires? Was is back by the boost solenoids between the firewall and engine?