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Homelink-project - Need Help

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took the plunge and bought all the parts needed to add the Homelink feature. Gert was really helpful and gave me a good price.

Installations of the parts is really easy: Just remove the cover, put in the buttons, wire the prepared power-harness to the circuit plate and the circuit plate to the transmitter, mount the circuit plate and the transmitter and you're done. You can't do anything wrong (at least that's what I thought).

BUT ... that darn thing does not work, dammit. :censored:

What I don't understand (probably because I'm to stupid):

- There's power on the circuit plate only when the headlights are turned on!?

- According to the manual, a fuse is needed on the right fusebox (no 42, 5A). But even if I remove the fuse, the buttons are still light when I turn on the headlights. It seems that the fuse doesn't have an effect at all!?

- There's never ever power on the harness from the circuit plate to the transmitter!?

- The control diode never lights up!?

Does anyone have an idea? Could it be that the feature must be activated through the PST2 at the dealer? But if so, why do the buttons come on when the headlights are turned on??????? (another power source for the transmitter is not possible because there is only one plug on the transmitter and that's the one for the harness coming from the circuit plate behind the buttons).

Any help, hints or comforting words are greatly appreciated.

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Hi Matt,

When you switch on the headlights, the 3 yellow LED's work as backlights for the switches.

I just checked out the circuit board for the buttons.

The connector with the 3 wires has the following configuration :

#1 : +12V headlights (to power the 3 LED's)

#2 : Ground for homelink module and backlights of the buttons

#3 : + voltage for the homelink.

Since the LED's work, it is sure that #1 and #2 are fine.

You need to check if you find power (positive) on the #3 wire.

Good luck.

Edited by Gert
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Many thanks for that quick reply, Gert and Loren,

Training the transmitter will be the last step. And unfortunately, I'm not there yet.

I just checked again and found out that there's no power on the wire #3 respectively fuse no 42!

That explains why this darn thing doesn't want to work. Now how can I get voltage on wire #3 or fuse no 42?

Could it really be that it needs to be activated with the PST2 or is fuse no 42 no even wired (but if so, why would they pre-wire up to the circuit board?).

Now worst case, there's no power on fuse no 42. I guess I couldn't just tap into an existing power source in the overhead console without the risk of damaging the transmitter if I don't find one with the appropriate voltage (which voltage does the transmitter need anyway???)? :(

Edited by SFMatt
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Next step is to be sure that Fuse 42 is directly connected to wire #3.

Fuses like F42 generally are installed in the main 12V circuit.

If there are no voltage reducers or resistors in the wiring between F42 and #3, I would try to wire the outgoing contact of F42.

You can always use a fast 100mA fuse.

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Yabadabadooooooooo! It works. :jump:

Fuse #42 is not wired up to the roof console and the power for the backlight of the buttons comes from the same line as the sunroof-button. This explains why the backlight worked while the transmitter didn't have any power (both wires on the same connector!).

So I had to tap into another switched power source. Et voilà, it works!

Many thanks again for your support, Gert!

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  • 5 years later...


Excellent !!!

Did you find a switched power source in the roof console?

If so, where?

I had the the same problem when I added the Homelink components. The Red #3 wire was not hot. My Cayenne did not have the park assist option so I used the hot Brown #6 wire from the unused Park Assist connector.



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  • 5 years later...

That is a great solution, mine also didn't have a switched supply so I connected it up and now it all works.  Had to replace a 'redneck repair' I guess PO installed kitchen cupboards...?  So bought the coplete thing from ebay with the homelink stuff and fitted it into the cayenne.  Had to paint the unit but all in all 2 hr's work and I can delete the remotes from the sunvisor.  Thanks for the wiring tip it worked out great!!!




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