Hello all this is my first time here.

My problem is in my detached garage that has its own elec service separate from the house (I get 2 bills). 100 amp service in the garage and 200 amp in the house.

I tried to install a garage door opener and the outlets in my garage won't run it, the motor does click and light bulb flickers. When I run an extension cord from my house to the opener it works perfectly. I tried 2 different circuits in the garage, both same result. Again, the outlets have power and lights work.

Im no electrician but I removed breaker box cover and everything looks secure I didn't poke around at all

Sounds more like a door opener installation problem than a electrical problem. Do you have the door safety light beam properly installed and aligned. Flickering lights sound like the electronic lock may be engaged.

It had no safety beam its an older opener. It was laying in the garage when I bought the house last year. When I plug the opener into my house outlets with an extension the opener works fine up and down with no hang ups

Lights have much lower power requirements than a motor.

In all likeliness there is a loose connection. It may not even be in your panel, it could be the service at the connection before the masthead.

You probably don't own a voltmeter, so you can't look at the voltage with or without a load, however, you could plug your toaster in in the garage and I'll bet it doesn't work properly either. Same level doneness in the same amount of time. Depends on how the toaster is designed.

If you plug it into your house and it works then something is going on with the service in your garage. What is on either circuit now that does work? Just some lights?

Can you run any heavy load on either circuit? Just for kicks, take your toaster into the garage and see what happens.

I'm thinking you have some corrosion, high resistance, on either the breaker or one of the buses. Is it aluminum wire?

Would you know if both circuits are on the same bus? It could also be a problem with the breaker itself.

If it is the service will my electric company charge me for troubleshooting?

@medic-dan all the wire is copper from what I can see in the breaker box

If it's between the pole and the panel or even the main breaker then no because they have to get involved. They are the only ones who can pull the meter.

Try the toaster.

It could also be a neutral problem, definitely one for the power company.