Low beams not working (sort of) and possible voltage surge
 

Wanted to get some thoughts on this one as I start to look into what's going on.

Got in the car leaving a restaurant last night and it was dark. Cranked the car and it was started fine. Pulled the headlight switch and it didn't look like the low beams came on. Dash lights were all fine. Got out of the car and the lights were on, but not putting out a lot of light. I have JWest's headlight relays installed and this is the behavior if you turn on the headlights without the car being on. Flipped on the high beams and everything was fine.

First thing I think is that the low beam relay is kaput. Started driving home with the high beams on. About a block from the restaurant the dash lights dim and then brighten. Looked up at the radar detector and it's display dimmed and then brightened. Then it was steady the rest of the way home. Detector has a voltmeter built in so I switched it to that mode. Read 14.2 while driving and 12.2 with the car off.

- Car is '83 SC.
- Detector is hard wired with with an in-line fuse.
- Dash lights are on a fused circuit.
- Turn signal stalk and headlight relays added ~18 months ago.
- Battery is Optima Red Top known to be at least 2 years old. Maybe older. I keep it on a Battery Minder when the car is not in use for more than a week or two. Car has been driven several times this week so it hasn't been gathering dust.
- I have been through the wiring in the last year. Grounds were all good. No corrosion. I redid the interior so I went through this stuff and tidied things up.

Dead headlight relay by itself doesn't worry me. The surge worries me. Is this a possible sign of alternator or battery going bad? 18 months doesn't seem like a long life for a headlight relay either.

Like I said, I haven't had a chance to do any more troubleshooting since last night. Just wanted to get some feedback on the surging.

first check your grounds. then check all the fuse connections. they corrode and cause problems. at a minimum it would tighten all the screw terminals on the block. one step above that i would remove each wire one at a time, clean the ends and the end of the screw and put everything back.

you can go have the charging system tested at advance for free.
if you crimped wires to the light relay, check those. i crimp and solder mine but i always give the wires a tug to make sure it is crimped good.
check the wires on the HL switch. run the switch in and out a few times. if the contacts are dirty, it can clean them.

Grounds were all previously cleaned and verified within the last 6 months.

Will double-check terminals on the block. Used posilock connectors on the relay connections.

Will check the headlight switch.

Forgot to mention earlier that the fogs don't come on either with the headlights.

Check for voltage spikes at the battery and at the engine. I'm currently rebuilding my alt, adding a new voltage regulator because I had spikes up to 16-17 every few mins at idle.

Does your Fasten Seatbelt Warning light flash on and off while you are driving? That is another common sign it can be the voltage reg.

Seatbelt warning light is currently disconnected. I'll look into that though.

What procedure did you use to check for voltage spikes? Just meter on the battery with the car idling? I can leave the voltmeter setting on the detector while I drive around but I'm not sure if that is a good test.

One of the things on the "to do" list was to replace the defunct clock with a voltmeter gauge. Why is it that you always need something before you can get around to it?

what are these posilock connectors?

Posi-Lock(R) - The Best Connectors You'll Ever Use!

They work great.

not familiar with them. at least they are not what i was thinking they might be.

when ever wiring has been modified, always go and check what has been done. even new factory connectors can have problems.

Hmmm... Tried swapping the 2 relays and still no low beam, only high beam.

What am I missing? I was expecting the problem to follow the bad relay.

Switch is working in that it is turning on the external lights and I get partial low beams but not "full" strength.

What headlights do you have? Got day time (city) bulbs in them?
What i'm getting at is....is it possible the low beams are not coming on at all and it's your city lights your seeing?
As for the surging voltage your VM in your detector will tell you if the charge voltage drops when the lights dim.

Hi...This is worth trying. With the HL switch on, try running a jumper from your chassis ground (by the battery-front inner fender) - Then on the ground return of your low beams, just touch the other jumper end... If the light gets brighter or turns on then the trouble is in the switch connection to the ground.

they corrode and cause problems. at a minimum it would tighten all the screw terminals on the block.http://www.gmum.info/5b.jpg

A new wrinkle. Last night I put it on the battery minder. This morning the low beams worked after I cranked the car.

Drove the car this morning on a good drive. No other issues. The voltmeter in the radar detector read a constant 14.0V while driving and 12.2 with the engine off.

Checked the battery date last night and it is 5 years old.

Maybe this is just battery going bad but it sure is odd...

Had the same problem but the turn signal switch was toast, only high, no low beams. Replaced it and all is good (on 70T). On the Carrera, 89. no high beams, only low and will replace that switch also when I have time. Good luck. Steve

12.2 volts with the engine off, following a recent drive is too low. I would expect anywhere from 12.6 to 13.2 volts for a battery in good condition. I hope it is as simple as needing a new battery. Disconnect the battery at one terminal and check the voltage across the terminals. If the reading goes up, above your 12.2 volts, I would suspect a short. Good luck!

When I got the car 2 years ago the ignition switch was bad, turn signal relay needed to be replaced and turn signal stalk had to be replaced. Headlight relays added at the same time. If the stalk were bad already, that would be highly suspicious, no? And the lights worked again this morning. KISS principle... there has to be something simple I'm missing. Connections look good.

Drove this morning and everything was fine. Voltmeter was reading 14.0. Parked for about 6 hours. Drove home in rush hour + holiday traffic bumper-to-bumper for an hour. Voltage dropped to 13.7 with the car running.

Let the car sit overnight to rule out charging system being a factor. Used my multimeter this morning and battery checked out at 12.56V which looks to be about 95% charged. I guess I could take it to a FLAPS for testing but I don't think this points to a bad battery - although it is 5-6 years old so maybe I have a cell going bad.

If it is a bad battery, I don't understand why it would crank and all other electrical seem to work fine EXCEPT the low beams. That just doesn't make sense.

Is there anything I'm missing here? I think I've done everything that was suggested. Checked connections, grounds, fuses...

Hi Tirwin... Another 2 cents worth - IF it happens again I think that I would check the voltage right at the headlight connection and then at your fuse/relay. Then at least you would know if it's in that section of the wiring. It just very well could be a bit of corrosion or poor connection on the headlight connector.

We also all know that the Ground connections 'Rule' on these machines so if at all possible run the bulb terminal electrical ground wire direct to the battery neg post with about a #12 wire to insure "no" ohms resistance on the electrical "supply" side of the circuit to the bulb element.