Electrical issue
 

I just started towing the other day, just a small landscape trailer, and since then I've had issues. Three warning lights came on at the same time, ABS, Suspension and ESP. They can be cleared by switching the car off and then on.
I took the car to my Indy and they were kind of puzzled. I told them I was towing and they think that the adapter harness may be the culprit. The car is factory wired for towing. After a little while he came back and said my brake switch needed replacing as it was overheating and I now had no brake lights. He managed to get them working again and ordered a new switch which I will have fitted tomorrow. On my way to work today, not towing, the warning lights came on again after about 25 minutes. I switched off and back on and they stayed off for the rest of the drive in, about another 15 minutes.
Thing is, was the switch the likely cause or was it something else (towing wiring or even the trailer) causing some kind of overload?
Anyone else have similar issues or have an opinion?

Plug in the VAG and get the DTC's, electrical gremlins in every Audi are a PIA to troubleshoot.
 

Next time the lights come on, try not to restart, instead get the codes and take it from there.

Re: Plug in the VAG and get the DTC's, electrical gremlins in every Audi are a PIA to troubleshoot.
 

I don't have a VAG but I'll see what the Indy is using tomorrow. I'm sure the lights will be back on by then. He didn't mention any specific information that he may have got from a VAG tool or similar.

The brake pedal switch is the #1 cause of the three light syndrome..
 

a very common malady of the allroad.

Just had the same three lights - dealer said all three systems use that relay, ergo three lights on

So, if I change the switch all will be good and towing wiring was not the cause but coincidence?

Could I have been feeling the over-heating relay?
 

When driving for the last few weeks, I've noticed a warmth on my left shin even though the windows are open and the heater is off.
Related?

you may have a problem with the trailer's wiring...
 

Does this trailer have a brake system? If so what kind?

How many lights are on it? Directional, Reverse, Brakes, running, etc.

They could be drawing to much and causing the heat build up. I've towed my small sunfish trailer and a giant Uhaul both with no problems.

Brand new trailer, no brake system. Just a 2 light system.

it should not be the cause of the problem....
 

unless your wiring to the Euro Plug is wrong.

The brake pedal switch is known to go and the timing may just be a coincidence with the trailer.