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Finally got the color "close" on my new LEER cap (a whole nightmare story of it's own, finally having it re-painted locally).
Place that installed cap found and tried violet/white wire that is marked by Ford for high mount
brake light. That didn't work for them, so they then used some kind of small "module" connected
to both brake lights, with a 3rd wire going to topper brake light. Topper brake light still didn't work
and I told them stop messing with it, I will figure it out.
I tested voltage on Ford supplied wire and have nothing, even though brake lights and stock high mount brake light work.
Only fuse I can find listed that seems to apply, inside or out, is brake light switch. Assume that is OK, as all the brake lights work.
The little "module" they put in, gets about 9 volts out of it when brake lights on, but also switches on/off when turn signals
used. What ever that little thing is, it at least it isolates left and right brake ight/turn signals, as all that works as it should.
I hooked a separate battery up to topper brake light and it's ground. Light does work.
So is there some other fuse I should be looking for or should I now go back to Ford and find out why I get no voltage from
that high mount brake light wire near spare?
Are you using the 4 pin connector for the trailer.
This is how it wired for my leer cap.
Thanks. I had stumbled on your pics searching on google. The wire they connected to on your truck, which I have (similar anyway), has no voltage when brake lights are on.
No, have not tried tying into 4 pin. Wouldn't that be the same problem, when signals make the "brake light" blink (even on a trailer)?
Another stupid question, does the key need to be on for that circiut to have power? No issues with my Century cap brake light, but can’t remember if I ever checked it with the truck off.
Another stupid question, does the key need to be on for that circiut to have power? No issues with my Century cap brake light, but can’t remember if I ever checked it with the truck off.
Hmmm. Good question. Stock 3rd brake light works without key on, but will check later today.
Looking at assorted posts here and on other forums, it doesn’t appear it needs to be activated in the BCM. Hopefully it didn’t get smoked in the shop the first time they tried to hook it up before resorting to the separator.
Looking at assorted posts here and on other forums, it doesn’t appear it needs to be activated in the BCM. Hopefully it didn’t get smoked in the shop the first time they tried to hook it up before resorting to the separator.
Thanks for the info. I am not real familiar with FET's. Do they typically reset themselves if the 'fault" is removed and/or can they be reset via a scan tool, like "resetting"/erasing a code
in the BCM?
Also sounds like there is another feed in pass kick panel. I finally found my pass through wires in there, so will look around (assuming it is the same color, V/WHT). Although if it is not working out by the spare, probably
not working on same circuit up by kick panel either.
A Field-Effect Transistor (FET) is a type of transistor that, when used with module software, monitors and controls current flow on module outputs. The FET protection strategy prevents module damage in the event of excessive current flow.
The BCM utilizes a FET protective circuit strategy for many of its outputs (such as a headlamp output circuit). Output loads (current level) are monitored for excessive current (typically short circuits) and are shut down when a fault event is detected. A short circuit DTC is stored at the fault event and a cumulative counter is started.
When the demand for the output is no longer present, the module resets the FET protection, allowing the circuit to function. If the circuit is still shorted the next time the driver requests a circuit to activate that has been shut down by a previous short ( FET protection), the FET protection shuts off the circuit again and the cumulative counter advances.
When the excessive circuit load occurs often enough, the module shuts down the output until a repair procedure is carried out. Each FET protected circuit has 3 predefined levels of short circuit tolerance based on the harmful effect of each circuit fault on the FET and the ability of the FET to withstand it. A module lifetime level of fault events is established based upon the durability of the FET . If the total tolerance level is determined to be 600 fault events, the 3 predefined levels would be 200, 400 and 600 fault events.
When a tolerance level is reached, the short circuit DTC that was stored on the first failure cannot be cleared by the clear the continuous DTCs command. The module does not allow this code to be cleared or the circuit restored to normal operation until a successful self-test proves that the fault has been repaired. After the self-test has successfully completed (no on-demand DTCs present), DTC U1000:00 and the associated DTC (the DTC related to the shorted circuit) automatically clears and the circuit function returns. The module never resets the fault event counter to zero and continues to advance the fault event counter as short circuit fault events occur.
If the number of short circuit fault events reach the third level, then DTCs U1000:00 and U3000:49 set along with the associated short circuit DTC. DTC U3000:49 cannot be cleared and the module must be replaced after the repair.
The BCM FET protected output circuits for the turn lamps system are the front turn and mirror turn lamp output circuits.
Have not tracked down where BCM even is and I'd guess it's not the same pin as a 10 year old F150.
I could not find this wire up near pass through wires by kick panel, even though it's claimed to be there.
Did find this tag on wire by spare, so I definitely have the right wire.
So, fired up FORSCAN, which just muddied the water some more.
Brake lights and stock HMSL work fine.
No codes for BCM
Looking at live data on BCM, these are the parameters I could find that applied.
Brake off
Brake applied
So BCM thinks brake switch is ALWAYS off, no matter what is really going on?
Did you ever figure out why the wire was not working? I am going through the same thing right now with my 24 super duty, found the wire with the third brake light tag on it but it is not working either.
Did you ever figure out why the wire was not working? I am going through the same thing right now with my 24 super duty, found the wire with the third brake light tag on it but it is not working either.
Nope. And the place that put on top, already hacked into my wiring, so wasn't like I was going to hurt anything trying out a different module.
The module works, and life it too short to leave my truck at dealer for days and weeks, AGAIN!!
