Gauge lighting intermittent

[eyespy]

Ive got a 99 GT, and once in a while you will turn on the headlights at night and the gauge pod wont light up. You can play with the headlight switch and dimmer and it still wont work. Eventually as you are going down the road they will come on with no more problems for a week or so. Seems like a bad connection somewhere.. Can someone point me to a connector to check or what to look at?

Thanks!

 

[wmburns]

There are other Instrument back lights than those on the cluster. What do they do? If the Instrument dimmer switch is used to dim the Instrument lights, do all of the other interior lights dim as well?

When the cluster Instrument lights go out, do the other Instrument lights elsewhere stay on? For example the radio, AC/heater control, and the back lite push buttons?

Check the ground to the left of the center console. It is shared by the cluster, GEM, AC/heater blower motor, and Radio.

If all of the Instrument lights are affected, replace the head light switch.

If just the cluster is affected, focus on the cluster connector. Clean the connector. Check for bent/pushed pins. Measure the resistance from the cluster pin #1 (BK) and pin #20 (BK/WH) back to battery negative. Post.

 

[eyespy]

Thanks for the reply. So far it has only happened to my wife and i am getting mixed answers when i ask what lights are going out. She claims only the cluster, that the radio, HVAC, etc are still lit up. I need to have it happen to me to confirm. If i goof around with the headlight and the dimmer i cant replicate it, everything seems ok. Maybe a cold weather thing.

 

[wmburns]

Recommend listening to your Wife. Even if she is wrong, the results are often better than the alternative.

Having said that, likely the plan of attack is the same anyway. If you pull the cluster, this offers an easy oppertunity to inspect the head light switch. More often than not, problems with the head light switch show up as overheating on the terminals anyway.

Once out, the cluster connector can be inspected as well as the printed circuit board itself. Look for evidence of overheating.

Don't discount a weak ground as the source of this problem. Again, once the cluster is in your hand, easy to confirm the grounds with a Ohm measurement.

http://www.latemodelrestoration.com/item/WPT165/94-04-Mustang-Headlight-Switch-Connector

http://www.latemodelrestoration.com/item/SW2275/94-04-Mustang-Headlight-Switch

 

[eyespy]

Happened to me this AM. The whole dash is out, the gauges work and the radio display works but all the HVAC lights and gauge lights are out. I drove about a mile and they still didnt come on. I played with the headlight and dimmer, still nothing. I then gave the dash a good bump with my fist right over the gauge pod and all the lights came on. So its definately a questionable connection somewhere. I will pull the cluster and see whats up, maybe unpluggnig things and re-plugging them back will freshen the contacts. I will look at all the grounds too. I would like to get my eyes on a schematic to see whats in the area.