My garage door currently will only go down with constant pressure on the wall switch. There is no red light on the beam, but when I connect it to power unit directly I get a red light. From this I suspect the wiring itself is bad. But I have a wire pair going to the light, and a wire pair going to the sensor, but only one wire pair to connect to the the power unit itself. Where and how do these two sets of wires come together?
Find the make and model of the unit - without at least that, it will be impossible to answer your question(s).
Once you have that, google ‘make model install’ - there should be a copy on the manufacturer’s site.
Did this ever work without holding the button down? That is a biggie - if it used to work witho only one side wired, you have that answered.
Yes, if I hold the button down it will go down. It is definitely the wiring. Right now I have it working but not fixed. Need some wire, and then I can rewire the whole thing.