Flickering Headlights Issue

Rick-sta · 18th December 2017, 16:11

Hi all,

I had a customer's 75 here today for a bi-xenon quad projector upgrade and we came across a bit of a problem. The car can't seem to handle 4 x xenon projectors, when 4 are running the outer to (factory xenons) keep flickering now and again. The xenon burners in the inner bi-xenon projector's I fitted work fine with no flickering.

Tested the bi-xenon lights on my ZT and they work perfectly fine, no flickering at all, there's definitely no fault with the headlight, burners or ballasts and I tried swapping all the bits just to be sure.

What we have noticed is that when standard headlights are fitted to the 75 (halogen projector or xenon) and the high beam is on, when I rev the engine the high beams dims down quite a bit every time the engine goes back to idle speed, and then gets brighter after about a second. Also when I increase the revs the high beam gets slightly brighter. So for some reason the voltage for the headlights keeps dropping, which would explain why the xenons keep flickering.

I've eliminated it being the battery at fault, as I tried a spare brand new battery and it didn't solve the problem. So would this be an alternator issue? Voltage across the battery is 14v and drops to 13v for a second or two after revving the engine.

The engine idles quite lumpy and isn't quite settled, not sure if that would be related.

Any input would be much appreciated

Cheers,
Rick

18th December 2017, 16:11	#1
Rick-sta This is my second home MG ZT 2.0 CDTI+ in Typhoon, MG TF 135 in Typhoon & Rover 75 Connoisseur CDTI SE in Pearl Black Join Date: Oct 2012 Location: Norfolk Posts: 7,534 Thanks: 2,718 Thanked 2,827 Times in 1,462 Posts	Flickering Headlights Issue Hi all, I had a customer's 75 here today for a bi-xenon quad projector upgrade and we came across a bit of a problem. The car can't seem to handle 4 x xenon projectors, when 4 are running the outer to (factory xenons) keep flickering now and again. The xenon burners in the inner bi-xenon projector's I fitted work fine with no flickering. Tested the bi-xenon lights on my ZT and they work perfectly fine, no flickering at all, there's definitely no fault with the headlight, burners or ballasts and I tried swapping all the bits just to be sure. What we have noticed is that when standard headlights are fitted to the 75 (halogen projector or xenon) and the high beam is on, when I rev the engine the high beams dims down quite a bit every time the engine goes back to idle speed, and then gets brighter after about a second. Also when I increase the revs the high beam gets slightly brighter. So for some reason the voltage for the headlights keeps dropping, which would explain why the xenons keep flickering. I've eliminated it being the battery at fault, as I tried a spare brand new battery and it didn't solve the problem. So would this be an alternator issue? Voltage across the battery is 14v and drops to 13v for a second or two after revving the engine. The engine idles quite lumpy and isn't quite settled, not sure if that would be related. Any input would be much appreciated Cheers, Rick __________________ How to retrofit Cruise Control on a diesel with no OEM wiring in place: Link How to retrofit heated electric memory seats with no OEM wiring in place: Link How to operate FBH and ATC via text Link How to restore cloudy projector headlights Link