Cab lights won't work

[garcia26233]

1999 ch613. This is how it happened and what I did.. My trailer's marker lights werent working, I checked the panel box on the firewall and everything was working. After that I checked the row of terminals above it, next to the coolant tank. There was the problem, bad contact due to little rust on my black wire, all others were fine. So I cleaned that terminal and checked it again with test light. IT WORKED !! Ok so when I was tightening terminal back on I accidentally touched the terminal next to it (white) which is ground and made spark... Hopeing it was only spark I put test light, Not working again ! but this time 2 of 3 cab lights not working either. I went back to panel box and everything seems fine there. I've checked inside panel box too and seems fine also went fuse by fuse... I checked the marker light switch and don't have any current there only the switch next to it which is for headlamps/other 3 cab lights. That's where I'm stuck now. Please help, I made a small problem bigger now

[redrider]

The only issue I've had(a couple of times actually) is the big red wire going into the bottom of the firewall fuse panel. That connection seems to corrode on me often. You wouldn't think a heavy wire like that is needed for only a handful of lights. Maybe you've bumped that wire and it's damaged an already weak connection.

[garcia26233]

Finally I got lights to work ! The panel box on the firewall must be in more bad shape then what I thought. Ive had other problems with it before but I've tried to clean it well and all seemed well for a good while. Problem was that testing the relay was good and would pass current to the relays terminal BUT not the the wire. And to my buddy who replyed thanks and yes that red thick wire was very corroded, it broke when I took off the whole panel off and I also thought it was input current but actually it's output to the sleeper.