pulsating lights

[john sutton]

I noticed the guage lights and head lights pulsating a bit on my drive home last night. I put a volt meter on the battery today and got a steady 14.4 volts with the lights off and 14.3 to 13.8 or so with the lights on and the pulses on the meter and lights. Could this be the fault of the voltage regulator?

[SCHNELE]

It sounds like your voltage regulator is begining to fail.

[azasadny]

Yep, voltage regulator or alternator. Warren will know!

[glenncof]

14.4V sounds too high without load.

You may want to check for low fluid level in battery as it's likely overcharging. If so you may see corrosion on +battery terminal or signs of acid burns on carpet. This is symptom, not the problem.

Have charging checked. Personally I may take it to Sears since I use Diehards.

If regulator is integrated then alt should be pulled and taken to rebuild shop (~$100 with new reg.)

I had flickering on my '85. Brushes in regulator were worn out after 87K miles on rebuilt alt. Can't just replace reg in this case since slip rings were badly worn and new reg brushes likely breakoff.

[john walker's workshop]

probably wasn't acting up when you checked it. they go as much as 17V off and on. hook up a volt meter, set it on the seat and see what it reads when the lights are flickering next time.

[dshepp806]

Speaking of regulator instabilities,..Just yesterday, I noticed (crank-up then drive off for work), that the voltmeter I've attached to the cig lighter started showing a 15.4 VDC reading,..eventually she settled at 14.1 - 14.3 range,..only load being parking lights and radio....have any of you seen voltages above 15 at times?

I've not yet correlated the meter reading to what my Fluke meter would tell me AT THE BATTERY..(to ensure the meter at the cig lighter is metering accurately,..that is, relative to a bench grade meter,..(i.e.,: no resistive copper in line to the cig lighter).

Just wondering,..otherwise,..she's quite stable and predictable.....I just don't like seeing the plus 15 thing happening.....I would hope that the DME on mine (1989) has onboard regulators to provide even more regulation AT the DME rails. This is something I wanted to look in to, as any onboard reg on the DME would see heat....In fact, I wouldn't be surprised to find it's solder points as key reflow points to address DME- intermittent problems...

I hope to find time this weekend to break out my scope and have a look at various DC points in a time/amplitude "environment". I hate trash on the DC rails but have never looked at a car with this approach (although MANY serious electronics circuits within other environments).

All observations welcome...

Best to all,

[glenncof]

Check calibration on the plug in meter, just put the bench DVM in parrellel at the terminals of it with whatever voltage source near 12V. Then put the DVM on the battery and compare voltage plug-in in lighter near operating conditions. >

I would suspect charging profile of v reg.

[dshepp806]

yes,..might as well use the Fluke at the cig lighter point (not trusting ((YET))) the chinese meter)...

Best,

[john sutton]

OK, More info...
the car is a 1970, with a separate voltage regulator, which I just got through replacing with one from Pelican Parts, it was a bosch.
The problem still exists, my mechanic who is fairly knowledgeable, suggested that the problem could be that the brushes may be the problem. I would be willing to replace the brushes if I can find them, but the mechanic said that he did not have the proper "gig" to reassemble the alternator. Do you really need a gig, and could the problem really be the diodes as opposed to the brushes...
The car still runs great, the batteries get recharged, and I'm wondering if I should just live with the pulsating, but I just hate to have anything wrong with my "baby".
Ain't electrons just @#$%^ wonderful.......

[nhromyak]

I lost my radio's amp when my regulator went out. I might have fried a part of my DME. My DME died one year later. I doubt you have a DME (unless you did a conversion). But you could lose the CDI box, or your radio if you get too much voltage.

Good luck.