Problem with tail lights 73 chevy

[tbrown]

Both of my turn signal lights on my 73 Chevy blink at the same time. This started after I was working on cleaning up the trailer connections in the back of the truck.  I traced the signal light wires back to the short, 4 prong female plug coming out of the firewall. Both the yellow and green wires going into the plug from behind the firewall flash at the same time when I put the tester on them. I pulled the steering wheel and looked at the white plastic signal switches. The look pretty good, however I have ordered a new signal switch assembly. Does anyone think I am on the right track or could the problem be between the firewall and somewhere else?

[outlaw70nova]

My guess is somehow you've tied the green and yellow wires together at the 4 prong connector. If they are touching one will power the other.

[BiggG74]

Isn't there a connection on the bottom of the steering wheel where you could check before you throw a part at it. I believe it's at the base of the column. Connected to your turn signal/horn switch.

[Irish_Alley]

im going to go on a limb here and say bad ground at the rear where you were cleaning. since it worked fine before you touched it now its acting funny

[tbrown]

Thanks for the three comments. The problem was the green and yellow wires touching within the signal light harness at the base of the steering column.