Post lights on panel intermittent

[kep5niner]

I’ve got the typical post lights for each gauge on my instrument panel, and several of the lights are intermittent. I’ve troubleshot by replacing bulbs, but some of the lights still don’t come on, or if I touch or tap them, they will light up. To replace the bulbs, I just pulled on the light, but it looks if I want to dig any deeper, I’ve got to come from behind the panel.

Any ideas or anything I’m missing on how to get all of these lights to consistently work?

 

[Dan Thomas]

I’ve got the typical post lights for each gauge on my instrument panel, and several of the lights are intermittent. I’ve troubleshot by replacing bulbs, but some of the lights still don’t come on, or if I touch or tap them, they will light up. To replace the bulbs, I just pulled on the light, but it looks if I want to dig any deeper, I’ve got to come from behind the panel.

Any ideas or anything I’m missing on how to get all of these lights to consistently work?

Often it's just oxidation of the contact in the bottom of the bulb socket. Scraping it with a small screwdriver can clean it. Power off, of course, or you'll pop a breaker.

 

[Stewartb]

Or a bad rheostat.

 

[Greg Bockelman]

Or a bad rheostat.

Wouldn’t a bad rheostat affect all of the bulbs?

 

[kep5niner]

Thanks for the feedback fellas. The rheostat operates normally for all lights, so I think I can rule that out. In looking closely at the contact points for the bulbs, some do appear a bit chalky. In an ideal world, I’d love to spray them down with battery terminal cleaner, but don’t think that solution is conducive to the panel environment.

I’ll try to scrape the contact points with a small screwdriver, then go back together with a light coat of dielectric grease. Thanks for the tips!

 

[zodiacflyguy]

I don't know what aircraft you have, but on a lot of 152s and older 172s, the wiring for the post lights is glued into crevices on the back side of the plastic face of the panel. Some times the wires can work loose from the sockets. Pain in the ass to get back together. Not as hard as getting the window spring back into the door frame, but still a frustrating job.

Sent from my SM-N960U using Tapatalk

 

[NordicDave]

I don't know what aircraft you have, but on a lot of 152s and older 172s, the wiring for the post lights is glued into crevices on the back side of the plastic face of the panel. Some times the wires can work loose from the sockets. Pain in the ass to get back together. Not as hard as getting the window spring back into the door frame, but still a frustrating job.

Sent from my SM-N960U using Tapatalk

What Zodiac said. Another area to look, the lights are daisy chained together on a Cessna and the wires break strands over time the solder lug. Sometimes not so obvious given the tad of sealant to keep the solder lugs from touching the metal support panel hiding damaged joints.

 

[thomasdr72]

I finally just ditched all of the post lights and put a nice light on the glare shield... Problem solved ;-)

 

[Radar Contact]

Any ideas or anything I’m missing on how to get all of these lights to consistently work?

I attempted the same and gave up. Had them all removed. Used some ring lights on some primaries and have the under dash lights. Works awesome...easy to change the color/intensity and mounts easily under the overhang on 310’s.

 

[kep5niner]

Great feedback Kevin, I may end up doing the same. Although, I would like your panel soup-to-nuts, but I haven't found that PowerBall ticket yet! My plan (in a galaxy, far, far away) would do exactly what you've done so far, but alas, the Wife has a vote too!

 

[Radar Contact]

Great feedback Kevin, I may end up doing the same. Although, I would like your panel soup-to-nuts, but I haven't found that PowerBall ticket yet! My plan (in a galaxy, far, far away) would do exactly what you've done so far, but alas, the Wife has a vote too!

Thanks Pete! Ha ha...if I had won the PowerBall I would have TXi'ed the entire thing like some of the guys over at TTCF. I went for budget upgrades that offer the best bang for the buck.

While I haven't seen the final bill for the lighting part, the simple act of removing the post lights and adding the under panel lights was quoted at a very reasonable price. Mine were so bad that they thought it was going to be more expensive trying to get those old things running again. Good luck getting your interior lighting worked out. I truly hated how bad mine was for the past few years.