So, I've been suffering from typical jaguar problems; replaced head gasket, battery, leads that connect to the battery, etc. Now I might have to replace the alternator because when my car idles, the dash lights and speedo works perfectly fine, but as soon as I touch the accelerator pedal and rev it up, all the lights, speedo, tacho just shuts off. I've had people tell me it's wiring harness, alternator, battery, etc. I'm just really tired of this car and want to get rid of it for something worth my time.

 

Please see post #20 in this thread for details of how to check for excess AC ripple from the alternator:

https://www.jaguarforums.com/forum/s...7/#post2044851