WOT causes headlights to turn off?!?

C

ctnsupra1

NAXJA Forum User

Location

MD

• Jan 21, 2012

• #1

We received some snow last night and as I was driving home I gave it the beans at a light and spun the tires and around 3/4 to full throttle the headlights cut out and CEL turned on. In the past under full load during the day the CEL and ABS lights have come on but nothing else is affected. Turning the ignition off and back on clears the idiot lights.

Does this sound more like a wiring issue or a switch issue somewhere?

'95 4.0 AW4

 

Ecomike

NAXJA# 2091

NAXJA Member

Location

MilkyWay Galaxy

• Jan 22, 2012

• #2

I would suspect the head light switch itself and or the dimmer switch. Both are common problems, and vehicle movement like a road bump can trip them off/on before they die completely.

If it is 4WD, check for damaged sensor wiring near the driveshaft and e-Manifold.

 

1985xjlaredo

NAXJA Forum User

Location

Kansas City

• Jan 22, 2012

• #3

Check your motor mounts too could be something going on if you have severe engine movement going on. Does it only happen at increased throttle application, or does it do it when you hit bumps too?

 

C

ctnsupra1

NAXJA Forum User

Location

MD

• Jan 28, 2012

• #4

1985xjlaredo said:

Check your motor mounts too could be something going on if you have severe engine movement going on. Does it only happen at increased throttle application, or does it do it when you hit bumps too?

Click to expand...

Motor mounts are solid, replaced stockers with Brown Dog less than 2000 miles ago. It doesn't happen on bumps, only when I get on the throttle. I tried it again tonight and it happened, it was a little scary when passing a car and the lights when out...

 

Ecomike

NAXJA# 2091

NAXJA Member

Location

MilkyWay Galaxy

• Jan 28, 2012

• #5

Have you pulled the CEL code history yet? What are the codes?

 

1985xjlaredo

NAXJA Forum User

Location

Kansas City

• Jan 28, 2012

• #6

I would pull those codes and see if they lead you anywhere. Sounds like a wiring issue. Weird that the ABS and CEL come on during the day. Could be a PCM issue but I dont know if that would cause the headlight debacle. Lets see those codes for sure

 

C

ctnsupra1

NAXJA Forum User

Location

MD

• Jan 31, 2012

• #7

I got on it coming up my drive and got the CEL to come on and counted the lights, it came up with a 12 and 41. Those codes equal Battery or Computer recently disconnected (12) and Alternator field control circuit open or shorted (41).

The alternator is less than a year old, a few thousand miles on it but it's a 136a unit from either a Durango or ZJ, can't remember which. Besides checking the obvious little black box connections on the back of the alternator, any things to look at to try and isolate the issue?

 

Shorty

NAXJA Forum User

NAXJA Memorial Lifetime Member

Location

on the beach in Ocean View, VA

• Jan 31, 2012

• #8

check that your battery is solidly mounted and the cables are tight. Hard acceleration might be causing it to move and disconnect-- that'd give you loss of battery code and would interrupt the field circuit to the alternator.

 

souske

NAXJA Forum User

Location

The land of competition

• Jan 31, 2012

• #9

I suspect that its not that your headlights are shutting off... per se
It is far more likely the light is dripping out the back of the housing.
Install hood vents and report back if they light up at WOT

 

C

ctnsupra1

NAXJA Forum User

Location

MD

• Jan 31, 2012

• #10

Finally tracked the culprit down and it was a connection I couldn't see without removing the battery. Everything was quite secure (Optima blue top with about 1000 connections) and so was everything on the alternator. It was my alternator to relay box connection that has a 150 amp blade fuse box that had loosened itself up. Thanks Shorty for getting me pointed in the right direction.