Battery or Alternator?

[Sierra John]

Is this an indication of a bad battery or alternator, or something else: When I'm idling at a stop light, my turn signals stop working. As soon as I give it some gas, they start working ('66 with 390). Starts up fast, but it does sit a lot. Any ideas?

[BrianC]

The sequential turn signal system on these cars need a certain amount of current running thru them to function correctly. I would check the voltage on slow idle (500-600 rpm) from your battery and make sure it is 14.5V...If it's lower than 14V you may have a bad regulator or battery as a starting point.

[Tbird100636]

Do the turn signals actually stop working or does just the clicker stop working? The turn indicator relay under the dash has been known to stop clicking when sitting at a stop, the signals are still working but the clicker stops clicking and the fender indicators stay on solid. Definitely make sure the charging system is working first. If it's ok there is a how-to on here opening up the indicator relay and bending the contact arm so it works better.

[Sierra John]

Thanks for the advice. The battery seems to be all right. I tried adjusting the turn indicator relay under the dash, and that seems to be the solution. Still needs a little fine tuning, though.

Appreciate the help.

[scumdog]

My '66 does something similar - with the turn-signals going when the car is at idle the indicator light (on the fender) 'pulses' instead of blinking,, driving along with a fre revs on they blink OK.

It will also do it if I'm doing 30mph and then I touch the brake pedal, it's almost seems like the voltage drop with the load the brake light create causes the indicators to 'pulse'.

[David Langhorne]

I had this problem for years along with poor starting although battery was charging at 14v or so. I eventually narrowed it down to the battery to body earth wire with an ohm meter - not a poor connection but the wire itself maybe at the crimped end. I think you have an earth problem which could be almost anywhere.
The fender lights themselves are just grounded to the fender by the fixing bolts which could possibly corrode or the rear lights also may have poor grounds.

[mnpetri]

Good info - thanks.
I've got the same problem... will check voltage at battery first.