99 Jeep Sport

[Kimbobba]

Hi,I'm new here,Hope you can help. we recently bought a 99 Sport.Thw problem is,that when we turn on the defrost or air conditioner at night,the head lights dim out every 40 seconds, very noticable,.One dealer told us this was normal.So we went to different Dealer they put on new altinator,Still does it, Any body had similar problem , and what was there causing this to happen,Thanks

[Christopher]

It's because of the A/C clutch engaging.The A/C system draws a good amount of amperage and when it cycles on and off the lights may dim a bit.When it's in the defroster mode the A/C is engaged.This same thing happens on my wife's 93 Cherokee Country and it has 105,000 on it with no problems-I wouldn't worry about it.

[XJEEPER]

My 99 Cherokee sport also does the same thing it is quite annoying.

[Christopher]

UPDATE.... There is a Tech Service Bulletin #08-34-99 that addresses this problem.It involves installing a relay module to correct it.

[Questions]

If I had a penny for every time I heard about that problem.....

well... I'd still only have about 15 cents...
hehe...

had an 89 cherokee laredo that needed a new alternator b/c of constant battery drain and such. after we had that changed it was not as bad. I now have a 98 sport and have not noticed it even with fog and head lights on. I have heard that cherokees have 'wimpy' alternators from a few different people. in my old 89 I just made sure everything was off b4 i turned the car off, and that seemed to also help.