Let me begin by saying hello im new here and appreciate the opportunity to ask my questions. Also, sorry for the long post but I am at a bit of a loss on this one.... That being said I am not 100% sure I am posting in the correct category or forum in general.

Long story short I was working on some what was supposed to be "basic" electrical for my GF's parents today but I have run into a snag and I cannot figure out for the life of me what is going on exactly. I will try to post pictures below so that you can get a better idea of what the issue is but ultimately there are two single pole toggles in the garage for the lights. One goes to the outdoor light over the garage and that is all that I know of .... the second is running the interior garage lights or was supposed to. What I have run into is when I replaced these two switches EXACTLY as they were before but with new white switches the interior fixtures stopped working. I got my voltmeter out and starting doing some basic diagnostic work and what I found was that the Hot wire going to the first switch shows to be correct and it is jumped to the second switch for power to that one. However, when I turn on the toggle for the interior lights I got no light and the voltmeter actually showed a DROP in voltage at the switch level ...so I proceeded to step 2 in my mind. I pulled the main fixture down and found a cluster of wires that I was not 100% sure of ... After lots of trial and error I think I have a bead on what MIGHT be going on here but wanted some much more professional/better advice than my mind can create.

What I THINK is going on is as follows:
I have identified a constant source wire up top behind the fixture ( one of the black wires )
I have also found a single red wire which after trial and error found out is running the garage door opener outlet also in the ceiling from the constant wire mentioned above.
2 of the other wires appear to be the commons/whites that were tied together before i started tinkering
and there is also another single black wire that I BELIEVE is a switch wire and acts the very same as the switch for the interior garage lights ( using the meter if i go constant to this wire it shows 20v, then i turn the switch and it drops to 0).

I hooked things up so they could use the garage door opener for tonight and tomorrow morning but I would love to try and problem solve this if i can and get the lights working as well as the opener. Keep in mind this house is 40+ years old so no telling what has actually been done before they moved in. Also I am NOT an electrician but I enjoy learning and doing residential stuff as a hobby away from my main job. I am no expert but I am also not a total and complete inept problem solver. Any ideas what could be going on or where I should go from here? There were a few more steps involved but I felt this is long enough. We did even go buy a new light fixture to ensure it was not something inside a socket or something simple. Any advice or commentary would be greatly appreciated! Tried to put all the pics into one sorry if they are not clear or confusing.

 

Welcome to AAC!

This forum is okay. Your post would be easier to read if you used paragraphs to organize your thoughts.

Have you verified that the interior light works if you replace the original switch?

 

No they do not work now... I guess I kind of made a mess and during my attempt to repair my work I fell into another riddle. From what I recall I believe the original wiring job had the constant up top going to the red wire and the switch wire with a pigtail off the switch wire to the first light fixture. But i cannot figure out why the voltage would be dropping when I turn the switch on. If im not mistaken wouldn't the voltage go from little to none and then go to 120 ish when the switch is thrown?

 

No they do not work now...

If you wire the original switch as it was originally wired, and the light doesn't work; you must have done more than just swap switches.

From what I recall I believe the original wiring job had the constant up top going to the red wire and the switch wire with a pigtail off the switch wire to the first light fixture.

It seems unusual that there would be a red wire on a single switch. Even three way switches typically use only black (hot) and white (neutral) wires.

But i cannot figure out why the voltage would be dropping when I turn the switch on. If im not mistaken wouldn't the voltage go from little to none and then go to 120 ish when the switch is thrown?

You should be seeing 120VAC or nothing. A significant variance would usually indicate poor connections; which can lead to fires. The expected voltage depends on where you take the measurement.

 

We swapped the fixture as well thinking the ballast was bad and when we started doing wire swaps up top is when we got into this pickle because it was a very odd wiring job to me so we started trying to figure out what was what and regrettably made things worse trying to diagnose and troubleshoot. I am bad about making my own issues unfortunately.

The single red wire is in the ceiling box with the other congregation of wires and it goes over to the outlet for the garage door opener.

The wall switches from what I can tell are wired correctly. Hot going to one terminal of one switch with a jumper to the adjacent switch for power. Then the load wires off each switch running to their appropriate fixtures. Common/whites all secured with a wire nut in the rear of the switch box.

On the first switch my voltmeter will show 120v terminal to terminal in the off position and if I recall drops to 0 when the toggle is thrown. Should be in the pictures if they showed up. The second switch ( that is supposed to run the ceiling fixtures ) is the one showing 20v and then drops to 0 when toggle is thrown and the single black wire in the ceiling box acts the same way which is why I said I BELIVE it is a switch wire.

 

Should also clarify the first switch in the box is working correctly and that fixture turns on and off properly when the switch is turned on.

 

I can offer several possibilities. The first thing is that there may be a poor connection where the white wires are joined. THAT can cause all kinds of problems, including voltages that drop when switches turn on. If there are multiple wires under any terminal screw, those are often a source of problems as well as potential fire starters.
You did not mention if any of the switches are 3-way types, which often cause grief because the common terminal is in different locations on the different models. Also, even a few new switches have been defective straight out of the box.

So the very first question is are there three way switches involved? I am guessing that there is a three way switch inside the house that is intended to work with a three way switch in the garage to control the outside light. That is very typical. Then there should be a constant feed that powers the door opener and the switch for the inside lights. Are you able to see any of the wiring connecting the junction boxes? Or have they all been hidden behind the plasterboard?
What can be useful in diagnosing and tracing is the grounding wires. Either bare or green insulated, if they are actually grounded they can serve as a neutral side reference, and that is valuable for finding the problems.

What it sounds like is that there was a 3-way switch and now the wiring has been confused. That happens a fair number of times, and it is where I get called because folks get very confused. I am a problem solver by profession.

 

I have not read through the original post but here are my thoughts.

If this is lighting in a garage there should be two 3-way switches, one at the house-door to enter the garage and another at the garage door. These are there to be able to control the garage lights from either location. This complies with building code.

Are there 3-way switches involved?

 

Update on this issue after I slept on it for a night...

FIXED:::

I was correct in my thinking partially.... the switches were wired correctly and are BOTH working correctly. My brain was telling me to test them incorrectly... like i said originally I was testing terminal to terminal instead of terminal to common wire so my readings were incorrect... Totally my mistake my brain was shot after a long day of texture and paint before we started electrical.

I found that the constant for the switches i was dealing with was actually coming from the box in the ceiling that went through the garage door opener outlet and then looped back to the wall to provide power to the switch box. So what I found was without the constant to outlet connection in the ceiling there was ZERO power to the switch box. Once I figured this out this morning things went a little more smoothly.

So basically in the ceiling where things got crazy I found a constant power that fed the garage outlet wire which fed the switches. Then we had the 2 sets of common wires in the ceiling box, easy enough to tie them together. Then we had the additional single black wire I found was the actual SWITCHED wire from the switch box that I needed to control my fixtures.

So I made my connections in the ceiling box from the wires that needed constant power, tied my common/whites together with a pigtail down for my main light fixture. Also connected my now correctly functioning single switched wire in the ceiling box with a pigtail down for the fixture. Metered it out showed correct (0 with the switch off and 124 with the switch on,) mounted my fixture and made all connections, flipped my switch.... and ... BOOM GOES THE DYNAMITE! SHE LIVES!!! If any of that makes sense haha....

I appreciate any and all the help and suggestions I got! Once I figured out what was what... and that the wire in the ceiling was also the wire at the wall .... the pieces fell together and I got it all to work. Score one for the day... now its time for a freakin nap!!! LOL

 

All is well that ends well, at least, usually.