Sorry for the cross-over post from swedespeed, but I can really use some extra help...

Here is the gist of it...

After leaving a glorious day at the park. I turned the ignition switch and a plume of white smoke came out of the defroster/windshield vent. Smelling plastic, I popped off the fuse cover. The source of the smoke was behind the fuse.

Switched key off, confirmed no fire.

I took off the cover (which I guess conceals the CEM) and there is a large wire harness. The skinniest black wire in the harness is burned through. There is no black sleeve as far as my hand can reach behind the board.


The car turns over. But it will not fire...Like there is a fuel restriction. Chug chug chug, like out off gas.



Re-checked fuse in daylight hours and the fuel pump fuse (believe it is 34 - a 15a) was blown.

I found the cause, which was a lousy installation of a handsfree wireless phone. They tapped into the power supply and left the wires exposed.



After removing the CEM, I see that the black wire is coming from Relay CMI2. Not sure where it goes. I follow it as far as I can reach and the wire casing is still melted.



I guess the questions are...does anyone know where this wire goes? According to the diagram, it goes to junction 53/428. Does anyone know where this junction is, so I can follow it back?


ANY OTHER IDEAS???



I would love to drop this off at the local shop, but with the current budget situation (or lack there of), I am better off trying to tackle this by myself.


Thanks for a great forum. Fortunately, I only lurk around, since I have had a pretty decent run here lately. With exception to the incessant light bulb problem.



Thanks again.



GP
2001 v70 t5

 

The wiring diagram I have just shows the 53/428 power junction in the wiring harness. The power for this junction comes from the 11C37 fuse in the passenger compartment fuse box. CMI2 is associated with the RL door lock/window and this is where there may be a short but I am not sure why the wire fried without blowing the fuse. The diagram shows the wire color as red/black, I have 2002 V70 diagram. Did your car start after replacing the fuel pump fuse?

 

I was afraid to start the car without repairing the wire.

 

I think tomorrow, I am going to insulate the bad tap junction and clean up the fried wire by clipping and terminating. Replace the fuse with a 10 or 7.5 (instead of the 15 - to limit any damage) and try to start it up.

Mr. Tippy (who might be from this board) sent some V70 diagrams. I will take a look at those over a cup of coffee.

Is the passenger fuse box on the driver side? Seems like a dumb question, but I have seen several things labeled passenger, though they are on the driver's side.

 

Yes, the passenger compartment fuses are on the drivers side, end of dash. Which fuse are talking about replacing, I am assuming the fuel pump fuse you mentioned? The reason I ask is I noticed CMI 12 is associated with the fuel pump and you mentioned CMI2, could you have meant CMI 12? Fuse 11C33 in my wiring diagram is for the fuel pump.

 

That would certainly make more sense, since the back windows both function correctly.

But, I found a wiring scheme for the S60 and thought the wiring looks more like the CMI2.

One black wire joins other relay, CMI1. The other black wire (the one that's fried) goes where ever. Then there is a blue wire that goes somewhere. Perhaps I have the labeling mixed up, but it seems like the wires are on the side of the larger, more square relay.

FINALLY - PICTURES!

 

- OR - now that I have another look, it could be MA2, which is X-feed overload relay...

 

I believe this black wire is the ground wire for two relay energizing coils; relays 2/31 CMA2 and 2/30 CMA3. This is a small gauge wire and not meant to handle a lot of current so what I suspect happened is an internal short in one of the relays. These relays supply power to many fused circuits so supply a lot of current, 11C7-9 and 11C12-15 and I am thinking there was an internal short between power and this small gauge ground wire and it acted as a fuse and fried itself. Keep in mind this is pure speculation on my part.
Without the ground wire though the relays won’t close and you won’t have power to the fused circuits mentioned and one of these circuits is power to the CEM itself. If it were me I would consider replacing (if you can purchase them separately) the two relays in addition to repairing the ground wire and also measuring between power and ground to check for a short after the relay replacements and wire repair.

 

Thank you so much everyone. I have a couple of good ideas for the weekend.

To repair the wire, it looks like I have to remove the dash, however. Does this mean removing steering wheel? I most likely need a puller for that?

Looks like I will spend the better part of the work day researching dash removal!

I wish I could drop off my car like a normal person!

GP

 

IF everything from junction 405 is grounded through 31/6 (with exception of the 2 relays, due to the severed wire), could I not make an alternate path to to the ground directly from the CEM to complete the current?

 

That's what I was going to suggest, just find a good ground for the cooked wire and route a new wire to the ground. The only concern I would have is if the cooked wire damaged adjacent wires in the wiring harness. If you can determine that other wires were not damaged from the heat of the fried wire then re-routing a new wire should be fine. This still leaves open what caused the original short between power and this cooked ground wire though.
As mentioned I suspect one of the relays may have had an internal short but there could also be other causes. One suggestion I was thinking about is when you connect a new ground wire it will probably be wise to jumper in a fuse temporarily when first testing things out. I did notice the two relays circuits are protected by 60 amp fuses so it makes some sense why the fuse didn't blow and the wire did. One last thing, I looked at my car and it looks like you can access the wiring harness under the windshield cowl area, which is where the ground junction point is supposed to be (for the fried wire) and the 31/6 ground point is on the left side of the drivers foot well area. Routing the new ground wire directly to this point would be ideal.

 

Sweet. I already have it ready to go. But was waiting for a little support.

The original cause was most likely from the arcing created by a un-insulated tap junction on a bad hands free phone install. Left both wires exposed. The fried wire is melted to these wires as far as I can tell.

GP

 

Hot damn, it worked!

I tired the same thing yesterday and I got that "click-click-clicking" of a dead battery. All things considered, I was too hesitant to hook it up to jumper cables (now that I think about it, this wouldn't make any difference).

Anyway, with a little reassurance, I jumped it and she turns over fine and NO WARNING LIGHTS or ERROR MESSAGES!

When I have a little money, I may take it in to hook up on the computer and replace the security siren, which I learned this would prevent the sun roof from function. Anyone hear of this?

Never a dull moment with this car...but I will tell you one thing, I have a renewed sense of pride. I changed her oil this morning and now I am going to vacuum her out before i put it all back together.

Thanks everyone -

GP

 

Great news, it's good to hear your car is running again and yes I've read about the alarm siren causing the sunroof to malfunction. There a single data communication wire from the alarm siren to the UEM and this single comm wire is also shared with the sunroof module. If the alarm siren board goes bad it can pull the comm wire to a weird voltage level and screw up the data communication between the sunroof and UEM.