Get a voltmeter or test lamp and make some tests
You have a service manual?
Download one here:
You can thank AbodyJoe for the 72 manual
http://www.forabodiesonly.com/mopar/showthread.php?p=1970088617
More manuals and info here
http://www.mymopar.com/index.php?pid=31
Along with electrical diagrams which are SIMPLIFIED, are not always correct or complete, and don't have all the options, but are sometimes easier to follow
http://www.mymopar.com/downloads/1972/72ValiantA.JPG
http://www.mymopar.com/downloads/1972/72ValiantB.JPG
Now in the 72 manual in the first thread:
[ame="http://www.abodyjoe.com/pictures/Misc.%20car%20info/1972%20Plymouth%20Chassis%20Serv%20Man.pdf"]http://www.abodyjoe.com/pictures/Misc.%20car%20info/1972%20Plymouth%20Chassis%20Serv%20Man.pdf[/ame]
Turn to page 8-150, which is Valiant under -dash wiring
Find the turn signal switch connector on that page.........a long skinny connector with a ^ at the top. Here's what goes INTO the switch..............
brake light switch power anytime the brake light switch is pressed
hazard flasher output from the hazard flasher. This is hot at all times
With the key in "run" you have turn signal flasher output. Again, present ONLY with the key "on."
Look at the connector.
Very top wire is wire D4-18W, labled "stop lamp." This is power coming FROM the brake light switch WHEN the pedal is pressed going INTO the switch
4th from the top is wire D2-18R which means "circuit no D2" the wire is no 18 size, and it's RED. Notice that it's labled "turn signal flasher" This is power going INTO the switch FROM the signal flasher WITH the key turned ON
5th from the top is wire D32-18P, labled "hazard flasher" This is the output of the hazard flasher power going INTO the turn signal switch. It is hot at all times
The BOTTOM wire, the black, is the HORN BUTTON wire
All the rest are labled, left, right, front, rear, going OUT to the lamps
With the key OFF and everything plugged in normal, and the switch CENTERED and the hazard flasher switch OFF, You should have power coming FROM the hazard flasher TO the switch. That's the pink wire, 5th from the top. No other power should be on that connector anywhere under those conditions except for the black horn button.
NONE other
OUT you should have NOTHING. No left or right lamp wire should be hot. IF IT IS the new switch is BAD
