Trailer LED's pulse faintly when connected
05-09-2019, 10:39 AM
#16
Addict
Rennlist Member
Rennlist Member
The external light pulse was a known issue on the Gen1 Cayennes (2004-2009). Because most of the vehicle is run by electronic control units, most of the signals carried in the wiring looms are digital instead of analog. The pulse is the manifestation of these digital signals carried on the headlight/brakelight circuits and the subsequent mixing of analog and digital units on the same circuit. Porsche's firmware programmers (actually Valeo's programmers) never considered this situation in their designs and subsequent firmware that powered the control units and ultimately the overall vehicle. We had endless discussions and debates in the Cayenne forum about this topic "back in the day". Ultimately, those folks with the "early" Cayenne's and whose trailers had external LED lighting packages were left in a lurch. There was no way to overcome the faint blinking of the lights. The control units are looking for certain electrical values as signals regarding operation of the system. The original design of the firmware for these control units never contemplated an external LED lighting setup that would substantially lower the electrical draw when a trailer was connected to the vehicle. The control units were programmed to look for the draw produced by at-the-time "standard" incandescent lighting packages.
Don't ask me how I know........
Toby
Don't ask me how I know........
Toby
05-09-2019, 01:42 PM
#17
Perhaps I can be of little help. I have the same set up:
2016 Touareg TDI w/ tow package (same gen as yours)
Trailex 7541EB
You may already have done some or many of the below, but trying all possibilities.
1) Did you connect a brake controller to the factory wiring harness? It's below the dash and can be a PITA to get to (for some cars it's not, apparently). You can rig up your own harness or buy a pre-made one on eBay (using all VW parts and sold by a private individual - no relation other than as a customer). I have Tekonsha P3 but I've used other controllers as well in the past. I did this after doing much research on Touareg forums.
2) Based on my research, I got a connector from Etrailer.com. There have been some (or one person) who said it's not necessary, but I got one just in case. No idea if the connectors you tried are same. May not be a bad idea to try the one from Etrailer - you can always return it if it doesn't work.
3) My (trailer) LED lights will blink every several seconds if the lights are still on in my Touareg with the engine off. This was mentioned more than once in Touareg forums. However, mine do not pulse or pulse at other times. In other words: trailer connected but Touareg engine and lights off = no blink. Trailer connected but car is on with lights off = no blink (or pulse). Trailer connected but car is on with lights on = LED lights constantly on without blinking. Basically the only time I get LED blinking is when the car is off but the auto lights haven't gone out yet. Once the lights go off, the blinking stops.
Hope this info is helpful to you. My personal suggestion is to try out my combo above (and/or research Touareg forums) and see if you still have any issues. This info may or may not be pertinent to Cayenne owners.
BTW, I highly doubt Porsche/VW dealers or tech people will be of much help.
2016 Touareg TDI w/ tow package (same gen as yours)
Trailex 7541EB
You may already have done some or many of the below, but trying all possibilities.
1) Did you connect a brake controller to the factory wiring harness? It's below the dash and can be a PITA to get to (for some cars it's not, apparently). You can rig up your own harness or buy a pre-made one on eBay (using all VW parts and sold by a private individual - no relation other than as a customer). I have Tekonsha P3 but I've used other controllers as well in the past. I did this after doing much research on Touareg forums.
2) Based on my research, I got a connector from Etrailer.com. There have been some (or one person) who said it's not necessary, but I got one just in case. No idea if the connectors you tried are same. May not be a bad idea to try the one from Etrailer - you can always return it if it doesn't work.
3) My (trailer) LED lights will blink every several seconds if the lights are still on in my Touareg with the engine off. This was mentioned more than once in Touareg forums. However, mine do not pulse or pulse at other times. In other words: trailer connected but Touareg engine and lights off = no blink. Trailer connected but car is on with lights off = no blink (or pulse). Trailer connected but car is on with lights on = LED lights constantly on without blinking. Basically the only time I get LED blinking is when the car is off but the auto lights haven't gone out yet. Once the lights go off, the blinking stops.
Hope this info is helpful to you. My personal suggestion is to try out my combo above (and/or research Touareg forums) and see if you still have any issues. This info may or may not be pertinent to Cayenne owners.
BTW, I highly doubt Porsche/VW dealers or tech people will be of much help.
05-21-2019, 03:13 PM
#18
Racer
Thread Starter
Perhaps I can be of little help. I have the same set up:
2016 Touareg TDI w/ tow package (same gen as yours)
Trailex 7541EB
You may already have done some or many of the below, but trying all possibilities.
1) Did you connect a brake controller to the factory wiring harness? It's below the dash and can be a PITA to get to (for some cars it's not, apparently). You can rig up your own harness or buy a pre-made one on eBay (using all VW parts and sold by a private individual - no relation other than as a customer). I have Tekonsha P3 but I've used other controllers as well in the past. I did this after doing much research on Touareg forums.
2) Based on my research, I got a connector from Etrailer.com. There have been some (or one person) who said it's not necessary, but I got one just in case. No idea if the connectors you tried are same. May not be a bad idea to try the one from Etrailer - you can always return it if it doesn't work.
3) My (trailer) LED lights will blink every several seconds if the lights are still on in my Touareg with the engine off. This was mentioned more than once in Touareg forums. However, mine do not pulse or pulse at other times. In other words: trailer connected but Touareg engine and lights off = no blink. Trailer connected but car is on with lights off = no blink (or pulse). Trailer connected but car is on with lights on = LED lights constantly on without blinking. Basically the only time I get LED blinking is when the car is off but the auto lights haven't gone out yet. Once the lights go off, the blinking stops.
Hope this info is helpful to you. My personal suggestion is to try out my combo above (and/or research Touareg forums) and see if you still have any issues. This info may or may not be pertinent to Cayenne owners.
BTW, I highly doubt Porsche/VW dealers or tech people will be of much help.
2016 Touareg TDI w/ tow package (same gen as yours)
Trailex 7541EB
You may already have done some or many of the below, but trying all possibilities.
1) Did you connect a brake controller to the factory wiring harness? It's below the dash and can be a PITA to get to (for some cars it's not, apparently). You can rig up your own harness or buy a pre-made one on eBay (using all VW parts and sold by a private individual - no relation other than as a customer). I have Tekonsha P3 but I've used other controllers as well in the past. I did this after doing much research on Touareg forums.
2) Based on my research, I got a connector from Etrailer.com. There have been some (or one person) who said it's not necessary, but I got one just in case. No idea if the connectors you tried are same. May not be a bad idea to try the one from Etrailer - you can always return it if it doesn't work.
3) My (trailer) LED lights will blink every several seconds if the lights are still on in my Touareg with the engine off. This was mentioned more than once in Touareg forums. However, mine do not pulse or pulse at other times. In other words: trailer connected but Touareg engine and lights off = no blink. Trailer connected but car is on with lights off = no blink (or pulse). Trailer connected but car is on with lights on = LED lights constantly on without blinking. Basically the only time I get LED blinking is when the car is off but the auto lights haven't gone out yet. Once the lights go off, the blinking stops.
Hope this info is helpful to you. My personal suggestion is to try out my combo above (and/or research Touareg forums) and see if you still have any issues. This info may or may not be pertinent to Cayenne owners.
BTW, I highly doubt Porsche/VW dealers or tech people will be of much help.