Correct light bulbs

Joined
Jul 15, 2021
Messages
30
Reaction score
3
Points
8
I've started with making sure all grounds of my car ('73 Pontiac Catalina) are fresh, clean and tight since some electrical systems were having some issues. One of them was slow blinking turn signals. With every (light) ground cleaned (bulb housing, batt to body and so on) the lights were significantly blinking faster.

The only issue i have is: while i was in there i changed my tail, reverse, front turn and courtesy lights for new ones. After this my turn signals were not flashing anymore.. I've been thru changing everything back and forth, old bulbs, new bulbs making every combination to make them flash again. New vs old courtesy bulbs make no difference. But new vs old front turn and back tail lights do. Turns out they flash the fastest using the old bulbs. How is this possible? I used the correct bulbs (right?). The 1157 (12V/5W) bulbs. The old bulbs have a more copper/brass like metal body were they ground. Could this make them ground better and thus flash faster? Or did i use the wrong bulbs after all? Or, could a faulty flasher relay be the case? Picture shows old vs new bulbs

thumbnail_IMG_8686.jpg
 
So you haven't tried a new turn signal flasher?
 
Last edited:
So you haven't tried a new turn signal flasher?
Not yet. I will, but how would a new flasher work with new lights and the old one just with old (stock) bulbs? The flasher unit was replaced maybe 3-4 yers ago
 
If the load on the flasher is too low it will not flash. Usually happens when someone switches to LED.
______________________________
 
Changed the flasher today for a new one, still the same problem.. if the load was increased that would potentially solve my problem, but the bulbs are correct (if I’m right). there's no such thing as a 1157 6w or up
 
Can it have something to do with the voltage regulator maybe? I noticed the turn signals blink more rapidly when the engine is running. They also blink with the engine off but with headlights also off. Turning headlights on without the engine running means no blinks at all.

I don't know if early 70's pontiac had the VR build in the alternator or separately?
 
You didn't say in your initial post that the lights blinked with the engine running You said with new bulbs no flashing
Use a voltmeter to test battery with engine off and engine running.
Off, fully charged battery is 12.75, less than 12.5 check with engine running, should be 13.5 to 14.5. Regulator is inside alternator.
 
You didn't say in your initial post that the lights blinked with the engine running You said with new bulbs no flashing
Use a voltmeter to test battery with engine off and engine running.
Off, fully charged battery is 12.75, less than 12.5 check with engine running, should be 13.5 to 14.5. Regulator is inside alternator.
That's because I already tested the batt and charging voltage. Everything there is fine. It's just without engine running no blinking. With engine running. Exxxtreeeemely slow so almost dismissable. Fact is, with the old bulbs it's working. So my thinking it has to have something to do with the kind of bulbs or a regulator
______________________________
 
So what were the results of the testing?
 
So here are a few findings from the meter:

Batt voltage,
Batt engine off : 13.05V
Batt engine on: 14.64V
Batt engine Rev: 14.71V

Lamp resistance,

New lamp: 4.4/2.3
Old lamp: 3.8/2.3

Seems like indeed the older lamps have a lower resistance and so make the flasher blink faster..
 
Also nothing wrong with your alternator/voltage regulator
 
I would remove the bulbs and spray electric contact cleaner (CRC) in the bulb sockets, and on the electrical contacts on the bulbs before reinserting them. I had a trailer that was giving me problems saying the trailer was disconnecting and reconnecting as I was driving down the road. I disconnected the trailer plug, I sprayed in contact cleaner in the socket and plug before reattacing them and that solved the problem.
______________________________
 
I ran into that problem with my Cat , I ended up messing around with the turn signal harness connector at the column after replacing tail light sockets to get everything working again, everything was working fine till I decided to swap bulbs.
 
I ran into that problem with my Cat , I ended up messing around with the turn signal harness connector at the column after replacing tail light sockets to get everything working again, everything was working fine till I decided to swap bulbs.
Because of corrosion?
 
Because of corrosion?
The connections were bad I had to clean them with a pick and wire brush , it's very frustrating when that crap happens it doesn't make sense why just changing bulbs starts a chain of events that ends up being a ball game, I ended up going led lamps and led flashers but even that didn't work as planned the lights would not flash with all leds in I had to put old style bulbs in front to get the lights to flash , another strange thing with all led bulbs in when you step on the brake both turn signal indicators lit up .
 
if you go to LEDs you will need to update your flasher module on the fuse box usually round. It also forces you to check and or add motor ground wires.
______________________________
 
Back
Top