they said if I do put the new radio back in, and then the BCM blows again, it is my problem. I dont think they would know how to hook up the mic. They almost act as if the radio I put in is a aftermarket radio. I told them to fax the report to me, and then I will let you know what the codes are. Can you give me some reasons that the BCm blew up that would relate to me installing the NAV?

 

That is a crock - they cannot attribute the blown BCM to the radio - total BS and here is why. The output on the BCM that controls the backlighting is on a completely different circuit then the CAN BUS communication circuit which is what is used to control the backlighting on the radio, HVAC, trailer brake module, instrument cluster, etc. Those modules were fine.

Also, you had problems with your headlights not shutting off as I recall. More indication of just a bad BCM. The problem is that a FET (Field Effect Transistor) failure can be caused by a number of reasons:

1) Reverse current causes damage to the FET such that it no longer switches on. You'd have to somehow expose the purple wire to the vehicle 12volt system somehow and even then the current surge would have to be so signficant that it would actually flow backwards through the transistor. This could happen while making disconnections/connections with barrtery power still supplied. There is no indication of any wiring shorts/damage anywhere so I doubt the problem is systemic.

2) A FET is like a highly specialized solid state relay which is extremely reliable in normal operating conditions. However, they can fail if there is a fault during manufacturing. We are talking particle physic levels here so manufacturing quality control is very important. I've seen FETs fail for no apparent reason other than what is seemingly fate. But this is rare. I would guess better than 99% of FET failure is surge current related due to an unusual condition - usually not repeatable.

I'd love to take the BCM apart to see what kind of components they are using. I suspect the Ford engineers will have that BCM apart as soon as they get their hands on it.

To answer your question directly - if in fact the BCM blew as a result of the nav install, I think there are only two likely sources/reasons:

1) Static electricity from the carpet/you when you handled the radio.

2) When making the ACM connections, a surge current flowed through the wiring harness back to the BCM (as you stated you hadn't disconnected the battery). Now, while I stated the ACM dimming is controlled via the CANBus, there is a dimming circuit wire (that purple wire) that is in the ACM harness (although it is not used by the ACM) so that circuit is potentially exposed.

I can't prove or disprove this as the source but I'd say it is within the realm of possibility.

 

So if it was your truck, would you have them install the new BCM, then put my nav radio back in and just get It away from there? Because that is what my thinking is. I think when I disconnected the acm from the radio and then replugged it back, something happened to short the BCM. it's been 2 hours and still no fax. They said the BCM will be in tomorrow, so I think I'm going to do what I said earlier. Also is there a possibility that the bad BCM is causing my mic not to work? Could they replace the BCM tomorrow and the mic magically work?

 

I doubt the BCM and MIC issues are related. Did you see my comments above about the mic connections?

Do you have your truck or does the dealer have it? If you have it, I'd make the mic connection as per the schematic and try it out. It should work regardless of the BCM issue.

Then I'd tell the dealer to put the new BCM in with the Nav radio and get the hell out of dodge!

 

I was just hoping for a fairytail ending where it was all fixed in one wack. Haha. They have the truck. So I'm just going to tell them to replace the BCM reprogram it, leave the nav hooked up the way it was, and give me my truck. I can't be angry though because I can not rule myself Out as a possibility on goofing it up.

 

Sounds like a plan - good luck tomorrow and stay on them about getting you the diagnostics info - I'm really curious to see what it says.

 

Dealer just called back, says the BCM won't be there till Wed or Thursday. He also said he would NOT istall this radio back in. THe "Master Tech" says that the ground or something is bad in it. So when he removes the radio everything goes back to mormal, but when the radio gets plugged in the whole thing goes wacko. Hes sending the report soon, will you be able to tell from it if this guy really knows that the radio is bad? I just can't see it being bad, but you never know? I don't want to be out another BCM and programming charges.

Also, when i did the install, I canaballized the sirius radio DLP in the process as well as I cut off the wiring plug for the DLP to get some pins for the MIC. Do you have the part numbers for the DLP and the wiring harness end, so that if I do have to go to the orig. radio, it will still have satellite radio. I just don't think its the radio though.

 

?here is what I got sent. Any indication of the bad radio?

http://img3.imageshack.us/img3/1162/scan0001dx.png

 

Okay he is giving you part information only - those are only the codes reported by the BCM. All those codes say is the BCM output is bad. There should also be some network U codes if they actually did the diagnosis correctly.

I would also press him on what he means by the radio going wacko. Ask him for the DTC's that were reported when the radio was plugged in. They should be coming off the BCM, the ACM and network.

 

Does the dealer have your original radio as well?

 

No he does not. I'm at a huge crossroads here, either tell the dealer to put it back to normal, or just let them fix the BCM and hope it was that and not the radio. The thing is the radio worked perfectly in the truck, the only problem was the mic.

 

You mean this one?:



Part # WPT-647 Pigtail Harness

 

Yes. I'm pretty sure that is it.

 

Just to confirm, when you brought your truck into the dealer on Saturday (or this am, not sure?) your nav radio worked perfectly well other than the microphone? The dimmer worked fine on it as well, correct?

So what the heck have they done to the radio if in fact it is now going wacko as they say?

 

Thats the odd part. When I went in Saturday the only problems were the backlights and the mic. After I recieved the truck back, the headlights would not shut off. I don't think the actual radio is messing up. It's when he plugs it in then the system starts to act funny? Thats where my worry comes from. But with the bad BCM anything could happen I guess? I've made the decision to reconnect the nav radio when I get it back and just pray everything works. I'll disconnect the battery this time.