Towing

[convertvw]

Might not be the place to ask but am going to drive my Passat across Aus with a trailer and have read elsewhere about LED lights & rear parking sensor problems. Haven't bought the trailer yet, wanted to get to the bottom of it first if anyone has any experiences?

The whole tow setup is factory fitted with a 13 pin connection - will a simple adapter from an auto shop will be ok or not?

Cheers.

[Tom Caldwell]

LED trailer lights

Might not be the place to ask but am going to drive my Passat across Aus with a trailer and have read elsewhere about LED lights & rear parking sensor problems. Haven't bought the trailer yet, wanted to get to the bottom of it first if anyone has any experiences?

The whole tow setup is factory fitted with a 13 pin connection - will a simple adapter from an auto shop will be ok or not?

Cheers.

I have had a little 4x3 trailer for years. Last week I became sick of the unreliability of the bulbs. One had blown and the ends of two others fell off when I checked them.

"LED lights for me" - hang the expense. The led lights from Supercheap looked good but were expensive. Also they were 'square' and needed 25mm more space than the existing holders provided. The holders were also placed such that you could not get an angle grinder near the welds. Undaunted I removed the old holders by a combination of grinding, cold chisel and filing. Made up some more holders and wrestled with the wiring which initially made the lights do weird things.

The trailer fits on a VW Golf diesel with oem fancy very expensive VW wiring harness. No problem I thought.

In any case I persevered and by wiring the earth to the trailer and light earth wires to the trailer also it works (all light functions are happening). However as explained in another thread the light monitoring circuit on the dashboard shows its tell tale as a defective bulb as there is apparently no resistance in the led circuit. Elsewhere it i noted that Siemens designed a part known as VFET that provides the necessary smarts to make LED's work properly on the VW harness. The part is available as L-1879T from Lumen apparently.

However my specific problem is that when the car is parked with trailer attached all the trailer lights keep up a low-level flashing at intervals. Firstly fairly regularly and then an intermittant flash, stop, then another burst. If the trailer power plug is disconnected and reconnected the flashing stops and does not restart until the next use of the vehicle. I have not as yet tried but suggest that this low level flashing continues when the vehicle is moving. this is annoying to me and would also drive other road users crazy - maybe one could excuse it as a safety measure for old, slow trailer-travellers?

To my inexperienced lay mind it is as if there is a capacitor with residual charge that is discharging. However as disconnecting the trailer power stops it immediately it must be coming through the trailer harness from the car even when the car is 'off' and the car locked up.

Its a confounded nuisance and any help or advice would be appreciated.

Note that I have not fitted the Lumen part and although I get the bad-bulb warning on the dashboard the lights are working fine - consequently I presume that there is enough resistance the way I have wired things to make the lights work but not enough to satisfy the warning circuit. Furthermore the circuit from the car must continue to supply short bursts of power to all the lights for its own weird reason.

For help I tried the Supercheap store (enough said) as the packaging said nothing other than the very basics and no warnings whatsoever. Failing there I rang my friendly VW dealer's service desk. I was told bluntly that led trailer lights do not work on VW trailer harnesses but there was apparently a part costing 'about $200' that inserted into the line fixed the problem. He had no experience with the part as no one had bought one (unsurprisingly). However I told him that my lights were working. Surprised he had no answer for this mysterious low-level flashing effect.

Guess I will have to pursue this Lumen part # L-1870T as someone kindly has noted to this site.

Further dialogue on this matter would be welcome and I am determined to beat the problem. I have put a fair bit of work into getting working led trailer lights and to reverse the process is not only to go backwards to the dark ages of bulb reliability but not commercially sound.

One might think that a AUD$1,500 towbar/loom package might be better supported by VW Inc.

Tom Caldwell

[gtimk5]

Hmmm,
Introduction section?
Welcome....

[Tom Caldwell]

Since posting my information on led trailer lights I have found that Redarc make a part LDLIBT12 that applies a dummy load and fools the VW harness into thinking it is dealing with 'normal' bulbs.

I am following this up - seems a better solution than the Lumen one which from their catalogue seems to be a full harness with parts.

Led
Dummy
Lead
Indicator
Brake
Tail

are what the initials stand for and it is just a matter of connecting the various leads to the device.

Tom Caldwell