[gtrman59]

I have a 70 Mach1 and am having an electrical problem. My 4way flashers are working normally(sidemarkers as well)but with the 4was off, my left front turn signal lights on the parking light filiment and not on the turn signal one. the left hand side marker lights also don't work. I have a brand new turn signal switch. Could it be the headlight switch?

 

[79cobraII]

most likely a blub socket on the left turn signal has shorted out, try poping out the front left turn signal light bulb and see if everything goes back to normal. if it does you need to replace or repair that light bulb socket, they corrode and fail.

i had to replace both my front turn signal housings due to corrosion and grounding out.

 

[1109RWHP]

If the above suggestion does not work check all your grounds to the lights. it sounds like it is back feeding. My 66 would make the headlights and high beam indicator flash when you turned on the right t/s because of a bad ground.