TURN SIGNALS WORKING SOMETIMES

dickeymoore

G-Body Guru
May 6, 2009
992
129
43
Atlanta,Georgia
In my 1980 monte carlo the turn signals will work sometimes after I install a flasher in the fusebox,they may work for a day or stop then stop working now when I put a Flasher in they will not work, any HELP?THANKS
 
On a car that old, with presumably original wiring, fuses and switches, etc..."sometimes" usually means a wiring problem, or bad connection somewhere. Could be grounds for the front/rear bulb sockets, etc...

If you've replaced the flasher, the system isn't all that complicated in that it basically flows as follows:

1 - Turn/Directional Fuse powers the Flasher (blue wire in harness connector, or at least one of the two terminals in the fuse panel flasher socket) with the IGN on. Test light is the best way to check that. If one terminal lights the test light on/off with the IGN key turned on and off then your fuse is good.

2 - The Flasher other terminal (purple wire in harness connector, or the *other* terminal in the fuse panel flasher socket) that you didn't confirm in step 1 above goes to the Directional Switch in the Steering Column. You want to check that purple wire (with test light to ground) at the steering column directional switch connector when you have the flasher plugged in, IGN switch ON and either LEFT or RIGHT turn signal ON.

If you have 12v at directional switch connector that tells you the flasher is passing it over from the fuse but either the directional switch in the column is bad, the wiring leaving the directional switch is bad or there is a problem with wiring out to front/rear light bulbs/sockets, etc.​
If you do not have 12v at directional connector that tells you the flasher is bad, or the wiring from flasher to directional switch is bad (shorted or open).​
Few notes:

1 - Have you put LED replacement bulbs everywhere in the front/rear lights? If so, you need a LED compatible flasher because the LED's draw significantly less current than the original filament bulbs.

2 - Are you sure you don't have any bad bulbs, or corroded lamp sockets on either LEFT/RIGHT sides?

3 - It's probably easier to physically pull out every front/rear bulb socket and inspect them then to get under the dash for the checks above IMHO. If you see any white or black bulb lenses they're probably toast.

4 - You didn't mention if your HAZARD flashers work, and all four corners blink fine when you turn them on?
  • HAZARD flasher is separate at top of fuse panel, *and* get's power from different fuse, PLUS if they work that pretty much confirms that all the wiring OUT from the directional switch to the front/rear bulbs/sockets is fine.
  • If that's the case, the issue is isolated to the TURN signals only, and the steps I noted above are more likely to find the problem. Which would be the FUSE, FLASHER, Directional Switch or the under dash wiring between them.

Here is a link to MalibuRacing.com wiring diagram as a reference, they're pretty much the same across most GM vehicles from that era.

 
Like said, old stuff can be contrary sometimes. Intermittents and stuff like press on brakes and left or right lights up and other silliness is usually a corroded ground. If it keeps blowing fuses, ...short or back feed. Bad wire or bad ground.
 

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