The Tow-Pro Elite has diagnostics to warn of faults in the vehicle or trailer wiring. These are shown by colour coded flashes of the LED on the Tow Pro Elite’s remote head.
Yellow with 2 purple flashes can indicate either:
1. Intermittent trailer connection caused by:
2. A heavy short circuit on the blue output wire, caused by:
You can narrow down the location of the fault by disconnecting the trailer and put in some other load, for example, another trailer with electric brakes or a test light with a 21W globe.
If the LED on the Tow Pro Elite remote goes back to normal operation at this point there is likely to be an issue somewhere on the trailer you were using.
If the issue remains, it is likely that there is something on the vehicle that needs to be attended to, and it is recommended to contact a suitably qualified auto electrician for further assistance.