headlights keep blowing...........what up?

[surfingfreeman]

Hi All
So my 1982 fiat which i have had all of like 3-months is starting to act up (or perhaps im starting to act up). In a vain attempt to increase headlight intensity i bought one of the aftermarket double-relay kits to direct more power to the lights, well the installation went smoothly and both the low beams and high beams both got brighter, unfortunately after a couple of days the low beams burned out and then one of the high beams burned out, so i pulled up a wiring diagram and went thru the system checking for any obvious shorts or blown fuses and bought a new headlight switch and installed that, i then checked that there was voltage to the headlight switch and and to both the headlights sockets for the low & high beams, i then went out and bought 2 new sylvania halogens and installed them and checked the high and low beams which worked fine........for like 2 days then the low beams blew again and now only the high beams work so i checked the voltage coming out of the alternator with no lights on or other accessories and the voltage fluctuats between 14.4V and 18V volts, i then took the relay kit out of the headlight wiring system to read the voltages on low and high beam wires for both left and right headlights it read 14.7V however when i put the relay kit back in and read the voltages it was 15.7, the halogens are listed at 12.6 volts with 65/55W what is going on???????/ Perhaps time to go to the mechanic? Or do the brown wire fix? thanks for any carefully thought out ideas Cheers
Mike

































tem

[jimincalif]

18 volts!!! I'd guess the voltage regulator is the culprit. Should never see more than mid 14s I wouldn't think.

[surfingfreeman]

Hi Jim
Thanks for the reply, sounds like it's time for a new alternator.
Mike

[So Cal Mark]

and check the water level in the battery, voltages that high will boil all of the liquid out of it. I'll bet those lights were pretty bright

[surfingfreeman]

Well, 2-sets of mid-priced halogens and a voltage regulator later and i think i have fixed things, thanks for the comments everyone! Just to refresh all your inquiring minds, i had recently bought an after market relay kit to help brighten up my headlights a bit, so i installed it per instructions and about 2-days later my low beams fry, the next day one of the high beams goes at which point i'm running the "cyclopes" lighting system. So thinking that the lights might have just been gettin on in their old age i decide to go get a new pair of Sylvania Halogens, i put them in and same thing happens but the 2 high beams dont blow, i think they were rated a bit higher in terms of the power they can handle. So i recheck all my wiring connections and then check the voltage coming out of the alternator and sure enough it was all over the place from 14-18V, rather than throw away a nice Bosch Alt. i opted to hedge my bets on it being the voltage regulator which on this alternator is replaceable, so i got one for $28 and slapped that on and voila voltage stable at 14.2V..............for now. So the question this all begs is does a wiring system that has resistance in it cause a voltage regulator to die or was it just it's time? Thanks again
Mike

[Foster48x]

So the question this all begs is does a wiring system that has resistance in it cause a voltage regulator to die or was it just it's time? Thanks again
Mike

Does anyone know the answer to surfingfreeman's question? I'm about to replace the voltage regulator on my alt and am curious about it also.

Rick

[mdrburchette]

Did you see excessive resistance in your wiring? I believe it was just time for the regulator to give up the ghost. Shoot, the external regulators on the early cars hardly ever really regulated the voltage all that well

[Foster48x]

Denise, thanks for the reply. How do you check for excessive resistance in a system? I'm curious about other factors affecting the regulator only because the alternator is less than a year old. It is rebuilt but that just seems quick for it to already be toasted.

Thanks,
Rick

[kmead]

snip... It is rebuilt but that just seems quick for it to already be toasted.

I love the term rebuilt. What was rebuilt is the real question. Depending on the quality of the rebuild it may be an old one.

Often times a rebuild means replacing brushes, possibly bearings and skimming the face of the collector if its nicked. Testing the assembly to see if it generates the rated power and the regulator is holding it where it should be.

If the regulator tests fine it is unlikely it was replaced. A quality rebuild would probably replace the regulator.

Everyone is out to make a buck, for the most part a returned alternator will cost less to replace by the rebuilder than putting in a new regulator.

[mdrburchette]

You can check resistance with an ohm meter.

[Foster48x]

Karl, your right I'm sure it was a half-a** rebuild so the voltage reg was probably ready to go before I got it.
Denise, thanks I guess I need to learn more of the settings on my ohm meter .

Rick