Troubleshooting a jag

[Kevin Sevcik]

First things first, you can directly connect the jag to 12V with no breakers for testing purposes. If you have a CAN serial cable, you can use that plus BDC-COMM to do diagnostics on the Jag. Otherwise you'll only see a flashing yellow light without a good signal PWM signal.

Secondly, what color was it flashing when it wasn't working? Slow yellow means you don't have a good PWM signal or CAN network. Fast Red or Green means you're sending it a reverse/forward command. Slow red means there's a voltage, temperature, or limit switch fault.

Thirdly, the whirring you hear is quite likely normal. That's the cooling fan. On a 2012 Jaguar, the fan runs for 1 second after power on, and runs whenever you're sending a forward/reverse command.