ALT light flashing

[Russell J]

Hi folks!

I have a 1972 F100 automatic with idiot lights in the dash. My ALT light flashes, however when I check the charge rate to the battery it is just right (14.2 I think?) I definitely see pulsing in the headlights when they are on and the ALT light flashes in approximately the same sync. I aslo notice that when the headlights are off, but I do something to cause a light bulb to light up, i.e. press the brake pedal, the ALT light stops flashing. I've been through two voltage regulators from Advance Auto.

Troubleshooting suggestions please.

[cajuncannon03]

Check battery connections, and ground connection to both engine and frame

[Russell J]

Thank you. The grounds are new and tight.

The ALT light flashes off and on. Not flickering or anything random.

[Ranchero50]

If it's a rhythmic cycle, I'd replace the regulator. I've seen it before in the headlights, about 2-3 cycles per second.

[Russell J]

Rhythmic, yes. Like a heartbeat. This will be my third regulator. I know it's totally possible that the regulators have all been bad.

Does anyone have a suggestion for a solid regulator before I throw another $25 at one from a local parts store?

[Ranchero50]

I put an electronic one on from NAPA. I forget the part number but it was an option for the later model stuff. Old mechanical one strobed to lamps similar to a heartbeat.

[Russell J]

**UPDATE**

As I was rechecking my grounds as CajunCannon03 suggested, I found that the ground wire from the alternator to the lower mounting bolt of the regulator was loose...in fact, it could not be tightened as the mounting hole is stripped. (I'll get a slightly larger bolt to fix that) Therefore, I used the other mounting bolt of the regulator to ground the alternator. I'm happy to report that the flashing has stopped.