C-172 landing light switch

It's also over 40 years old (if it hasn't been
replaced in that time). Your problem could be as simple as that?

As I pointed out in earlier posts, Cessna 172s of that vintage had fuses and
mine was converted to new breakers of the same rating just last year.

Jim

Minor nit: He said the first one ("low beam") is the taxi light, and
then the landing light is "high beam". So, it would be turning the
taxi light on first, then the landing light on (and taxi stays).

"Low" beam may be a poor way to state it. It may well be the same bulb as the
"high" beam (landing light) (and I haven't actually checked to see). It is just
pointed much lower to the ground in front of the plane.
And yes, the taxi light stays on with the landing light effectively doubling
the load.

Jim

Recently, JFLEISC posted:

It's also over 40 years old (if it hasn't been
replaced in that time). Your problem could be as simple as that?

As I pointed out in earlier posts, Cessna 172s of that vintage had
fuses and mine was converted to new breakers of the same rating just
last year.

I still like the response that it could be a bad breaker best of all the
responses to this thread. A simple amp meter would tell you what is going
on. If the breaker is popping at a lower amperage than its rating, it's
bad. If not, it might be your voltage regulator.

Regards,

Neil

I still like the response that it could be a bad breaker best of all the
responses to this thread. A simple amp meter would tell you what is going
on. If the breaker is popping at a lower amperage than its rating, it's
bad.

This is not unreasonable except that the unusually large supply of fuses that I
found in the glove box makes me suspect that this is not a new problem.

Jim

On 05 May 2004 22:09:08 GMT, (JFLEISC) wrote:

I still like the response that it could be a bad breaker best of all the
responses to this thread. A simple amp meter would tell you what is going
on. If the breaker is popping at a lower amperage than its rating, it's
bad.

This is not unreasonable except that the unusually large supply of fuses that I
found in the glove box makes me suspect that this is not a new problem.

Jim

You have a surplus of 20-Amp 4AG (was AGS) fuses? ('61 172s -- the
club's anyway -- use 4AGs, rather than garden variety 3AGs, aka AGCs.)
Please email me -- -- if you want to get rid of
them. (4AGs are just slightly fatter than 3AGs. They're a
special-order item from Grainger.)

And for everybody who might have a fastback 172, please tell the NG
what kind of breakers you used. Ordinary rectangular ones seem to be
too big to mount vertically in the panel (because of the curve of the
metal at the bottom) and the holes for the fuse holders are too close
together to mount multiple breakers oriented horizontally.

And yes, we still have the generator and our landing light fuse pops
frequently, so you probably don't have a bad breaker.

Don

You have a surplus of 20-Amp 4AG (was AGS) fuses? ('61 172s -- the
club's anyway -- use 4AGs, rather than garden variety 3AGs, aka AGCs.)
Please email me -- -- if you want to get rid of
them. (4AGs are just slightly fatter than 3AGs. They're a
special-order item from Grainger.)

And for everybody who might have a fastback 172, please tell the NG
what kind of breakers you used. Ordinary rectangular ones seem to be
too big to mount vertically in the panel (because of the curve of the
metal at the bottom) and the holes for the fuse holders are too close
together to mount multiple breakers oriented horizontally.

And yes, we still have the generator and our landing light fuse pops
frequently, so you probably don't have a bad breaker.

Don

OK Don; Again my landing light breaker never trips, it is the generator
breaker.
I will look to see if I still have that box of fuses. (this now bothers me
because I know I had that stuff sitting around for at least a year and fear
that I recently threw everything out in a cleaning binge).
I got the rectangular ones to fit (admittedly it was tight). If you email me at
the above address I'll send a photo of the panel. I'm probably too computer
illiterate to remove any 'blockers'.

Jim

OK Don; Again my landing light breaker never trips, it is the generator
breaker.

That's two hasty mis-reads this week for me. I'm going to have to
slow down.

I'll email you about the photo. Thanks.

Don