But I how do I get brighter taillights. Prior to the installation of the relays the tail lights very dim to the point of not being able to see them. I did run new 14 gauge wire from the lights bulbs to relays. If I ran these NEW wires to the back of the dash cluster (where the original wires are coming from) will get it product a better illumination then the original wires?
Are we now talking tail or turn?
But in either case, you really need to do some troubleshooting. You could be experiencing voltage drop in ANY or more than one place in the circuit path
Let's take tail lights
The circuit path is:
From battery through fuse link, through bulkhead (main battery feed) to the ammeter, and the "in harness splice" This is a factory welded splice, taped up in the black ammeter wire, which branches off and feeds several things
From the in harness main splice, a wire from the ammeter circuit feeds the "hot buss" in the fuse panel.
The tail light fuse is connected to this buss, then a wire goes from the fuse to the headlight switch, and from the switch, up front to the park lights, and to the rear, to the kick panel connector, and on to the tail lights
So you could have drop at ANY of those points. Check the easy ones first.
BEST way is by checking voltage drop DIRECTLY. "Rig" a long piece of no 14 or no12 wire on one probe of your meter (covered and taped) and hook to the battery +, such as the start relay "big stud."
Turn on the park/ tail lamps, (YOU MUST CHECK UNDER LOAD)
and probe the fuse and fuse clips. You should not see much drop, a small fraction of a volt. If you do, you have already isolated the problem to between the fuse panel and the battery. So problem areas are the bulkhead main battery feed (that is the bulkhead itself) the ammeter circuit/ and "in harness" welded splice, or the riveted connections in the fuse panel for the fuse clips.
Look carefully at the fuse clips for rust/ corrosion, heat damage, looseness.
If you don't see much drop at the fuse clips, remove the kick panel and probe the connector for the rear harness. Pull it apart, inspect, and work it in/ out to scrub the connections clean, and feel for "how tight" the connector terminals are.
If you see a drop at the kick panel, but did not at the fuse panel, what is "in between" is a little bit of wire and the HEADLIGHT SWITCH. Time to pull it out and check it. Might be the switch, or just the connector
NAPA had one in stock for my 67, so these fit a lot of years, and are easy to get.
If you don't see much drop at the kick panel, the only thing to the rear is wire and the tail lights. Inspect the sockets for rust, "feel" for the tension of the socket springs. Try soldering auxiliary ground pigtails to the sockets and bolt solidly with toothed washers to the body.
AND LAST
Don't discount "old" or improper bulbs, or tarnished, dirty lenses and reflectors in your housings!!!
Good luck. This is a dirty job, but somebody has to do it!! LOL