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Diode Dynamics Switchbacks and BCM / Tail Light Issues
khsonic03
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FYI - I finally got around to doing the mod. Ended up using Diode Dynamics harnesses coupled with 1N5404 diodes and soldering everything directly to the Arrow's harness (green wire). Installed yesterday and seems to be working flawlessly. Thanks again for the write up!
ahl395
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Well I installed the diodes this weekend. Used the etrailer ones and the DD harness. Now my driver side headlight stays on any time ignition is on.... Wtf?
I thought it may be the Forscan programming so I changed that back but still have the issue. I'm sure the diodes are hooked up correctly because I wired them into the opt7s before installing so there's no way the headlight wire is on the wrong side of the diode.
Can anyone tell me their stock forscan codes for the following lines?
BCM 726-16-02
BCM 726-21-01
BCM 726-50-01
IPC. 720-02-01
BCM 726-45-01
BCM 726-26-02
BCM 726-50-01
I know that's alot of lines but it would be greatly appreciated as I'm not sure what I changed when I tried to fix the OPT7s way back when I originally messed with it and I'm thinking that's what's keeping my headlight on for some reason...
@Grimmer
I thought it may be the Forscan programming so I changed that back but still have the issue. I'm sure the diodes are hooked up correctly because I wired them into the opt7s before installing so there's no way the headlight wire is on the wrong side of the diode.
Can anyone tell me their stock forscan codes for the following lines?
BCM 726-16-02
BCM 726-21-01
BCM 726-50-01
IPC. 720-02-01
BCM 726-45-01
BCM 726-26-02
BCM 726-50-01
I know that's alot of lines but it would be greatly appreciated as I'm not sure what I changed when I tried to fix the OPT7s way back when I originally messed with it and I'm thinking that's what's keeping my headlight on for some reason...
@Grimmer
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Grimmer
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- #81
Info inserted above.
You can also get your original As Built from: https://www.motorcraftservice.com/AsBuilt/ using your VIN
ahl395
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Thank you sir. I will have to check those and see. I really don't know what else could be keeping the one headlight on. It's bizarre
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Grimmer
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- #83
If you don't find the answer in FORScan, I would start to wonder (after double checking the other wiring, of course) about a potentially defective harness from Diode Dynamics. It is strange that only one headlamp is on with the ignition. The FORScan DRL option to use the headlamps turns them both on with one setting, I don't think you can split them in FORScan.
It may be a complete pain in the butt depending on how much you have put everything back together, but you could try switching the DD harnesses between the left and right side of the car to see if the errant headlamp follows the harness. At first blush without all the details, it sounds like voltage may be getting onto the wrong lead at the headlamp connector. Perhaps some of the leads are shorted together within the DD connector.
It may be a complete pain in the butt depending on how much you have put everything back together, but you could try switching the DD harnesses between the left and right side of the car to see if the errant headlamp follows the harness. At first blush without all the details, it sounds like voltage may be getting onto the wrong lead at the headlamp connector. Perhaps some of the leads are shorted together within the DD connector.
ahl395
Well-Known Member
I was thinking the same thing myself. Going to swap the two sides and see what happens if the Forscan changes dont work.
I know there's no way to split it in the programming I was thinking maybe the BCM was confused by the programming I had to make the parking lights stay on while also having the diodes wired up. I guess we will see. I'll try the Forscan stuff tomorrow and if not swap the harnesses this weekend.
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Grimmer
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- #85
To my understanding, none of the wiring changes discussed in these thread should allow voltage onto the line that activates the headlamp. It would require that the wrong wire was tapped. Since you are using the DD harness and didn't tap them yourself, it might be some stray wire "fray" between two of the pins in the DD connector.
Do you recall if it was the Low Beam or the High Beam that is staying on with the ignition?
Do you recall if it was the Low Beam or the High Beam that is staying on with the ignition?
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Grimmer
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- #87
Pin 3 is the switched power that the DD harness is supposed to be tapping into to power the Arrow as DRL. Pin 10 is the Low Beam Relay. Pin 12 is the High Beam Relay. 50/50 chance for either.
If you have an Ohm-meter, it might be easier to test continuity between them than to switch the harness to the other side of the vehicle. A close inspection might also yield results. Check both sides, a short or cross wire could be on either side.
I suppose that it is also possible that DD assembled it correctly but that the connector itself was defective internally before they got it.
KilluminatiDre
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DD is doing 20% off and I want the front switchbacks but this thread is making me nervous.
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Grimmer
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- #90
Yeah, I've often wondered about separating them into two threads... Not sure if I even could.
The latest I recall about the DD switchback bulbs was that the BCM firmware in the 2015 MY was an issue and that it was corrected (and the 2015's could be flashed to the updated version). However, I have no personal experience with them and haven't tried to validate the claim that it was fixed against the responses from those with real world experience with the DD switchbacks.
The latest I recall about the DD switchback bulbs was that the BCM firmware in the 2015 MY was an issue and that it was corrected (and the 2015's could be flashed to the updated version). However, I have no personal experience with them and haven't tried to validate the claim that it was fixed against the responses from those with real world experience with the DD switchbacks.
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