issue w/ '70 Chevelle

[Sideoftheroad]

(old issue thought I would throw it out there) Headlights do not work anymore. Doesn't matter when I hit the dimmer switch. They used to work when I hit the brights, now they don't work at all.

 

Newest issue, bought new battery this past summer. Car ran fine. Let it sit for about a week and when I tried to start it up, nothing. Barring a bad battery cell, what else could it be?

 

Father in law thought maybe voltage regulator. I got a new battery tender for christmas and took it like 3-4 days to get a green light. That is w/out it hooked up to the car.

 

I figure a mouse chewed a wire, but not sure which one. When I look in the engine compartment, I can't find any frayed wires. Heck it is 40 yrs old now. Wouldn't be suprised if it is the original starter.

[mraf]

Sounds like dimmer switch to me. My 84 Ford F-700 dump trucks dimmer switch went out the last time I drove it. Clicked from low to high beam LIGHTS OUT. You sound as if you have a current draw of some sort when it sets. I had a 70 nova that did that, it turned out to be the alternator after checking everything else. Time to get out the test light.

[BuddyRich]

I'd guess Dimmer or headlight switch. There ain't much to them older cars. Turn on the headlight switch and see if you have 12 volts on one of the lugs from the dimmer switch plug. If not its the headlight switch. If there's 12 volts there then its the dimmer switch

[Sunrayman]

Sounds like you need a new ignition switch. All my dash stuff including my headlights acted funny when my 1976 corvette was acting up. A new ignition switch took care of it all...cheaply.

[Sailor]

My vote is dimmer switch. Had one that was the same. Turned out it was also drawing current when the car was off. Swaped it out and fixed the problem

[wes0778]

Simple stuff first! Didja check all the fuses? Have you checked the battery voltage? when it won't crank, does anything else like the dome light or heater fan run? If so, when you try to start it, does the dome light stay on or go out? Have you tried to jump starting it with another vehicle? Is it possible that the headlight bulbs are burned out? Check ALL grounding points. Just a few thoughts...

 

If the battery keeps going down while sitting for a day or two, two things I almost never found that was running the battery down;

1. trunk light didn't turn off when the lid was shut, bad mercury switch.

2. Glove box light did not go off when door was closed, door out of adjustment.

Edited January 13, 2010 by wes0778
more thoughts

[autopilot]

You "may" very well have a problem with the switch, but you said it took most of a week to get the battery back up to speed (albeit on a tender). Two quick & relatively easy tests; first...pull the battery, take it to Advance or Autozone and have them run a load test to make sure the battery is ok. (you might also want to take the alternator since the regulator is internal as I recall...they can test it as well) then you can mark either of those off the list of possible culprits.

 

Second, I think the switch was still on the floor if memoery serves.....pull the plug and probe the contacts of the switch with an ohmmeter..easy to see if the switch is good or bad. Then switch to volts and check the plug connector to make sure you have power comming to the high beam switch. If not, check the headlight switch itself; a little more difficult as it comes out the back of the dash panel. Do the same kind of tests as before on the switch and on the wires/connector supplying the switch. At this point if things are checking out ok, it's probably going to be an issue with the keyswitch.....just get a replacement and if it fixes it, it's done...(no sense in trying to figure out how to properly test it..just replace it)

 

*(If the switch is on the turn signal lever, find the harness connector on the steering column using the wiring diagram and color coding and disconnect the 2 halves; connect the ohmmeter leads to the connector terminals that go to the switch and cycle the switch. You'll find out quick enough if the switch is bad) replacing, if it is bad, is a whole other problem!!!

 

Assuming the switches are ok (which I'm not necessarily convinced they are, but IF), check your manual for the correct wiring diagram and check the headlight relay (if it has one) I don't recall if it does or not, so that ones for you to find out. If it does and you feel like you're getting out of your comfort zone, get one of your electrically savvy buddies to test the relay and make sure it works.

 

Last but not least, pull the headlights and check the lamps and more importantly, check the connectors for corrosion and / or broken wires. Also trace down the ground wire for the headlight circuit...it'll be a single wire to the frame or a common ground point (several grounds at one point).

 

There's one or two other possibilities, but they would be much, much less likey to be the problem. These above are the ones I've had to deal with personally ( and on one vehicle, I might add) Good luck !!!!

Edited January 13, 2010 by autopilot

[autopilot]

Just thinking about your problem some more......when I built my truck, I spent several weeks rebuilding various wiring harnesses, partly because of changes and upgrades I was making, but also because darn near every other wire I touched had the insulation all cracked and split......several of the problems I had to fix were spurious shorts to ground or broken grounds wires at terminal connectors. Most of the rest were shabby attempted repairs by previous owners that had no real clue what the heck they were doing. If you are not sure, have somebody look at it that is and have them make the tests to figure it out. Better than having a smoke test on the road somewhere!

[dray]

lets look at it in order first fix the starting problem check your battery if its good check the wires at the starter there is a small wire thats a fuseable link its made to burn in half to protect the wiring or it could just be the starter or starterbendix also make sure the wires are all making a good contact at the starter as everything runs through it

 

to test your charging system get it running and unhook one of the battery post cables if it keeps running turn everything on in the car still running its charging in good shape if you unhook the cable and it stalls you need a new/rebuit altnater

 

as for the lights you had this problem before the starting isue so like some one said change the dimer switch on the floor as they would get dirt and mosture in them and go bad

 

dray

Edited January 13, 2010 by dray

[footsie]

Check the silenoid switch on top of the starter too for cranking problems.

The headlights on that model are powered by the primary wire directly to the light switch then through dimmer switch. also check your bulbs, they could all be bad.

 

Gregg

[Yammer Dan]

I had one of those. Wish I had it back. Don't remember any light problems just couldn't keep tires on rear!!

[MiCarl]

What's all this about an ignition switch guys? The headlights on a 70 Chevelle wouldn't be wired into the ignition system at all.

 

Sounds likely it's the dimmer switch. If it is a floor mounted one the odds go up dramatically (windshield leaks, wet boots, holes in floor etc. help them corrode). Fuses, connectors and main light switch are other things to look into.

 

Battery tenders typically put out 1 amp or less. Talking about hundreds of hours to charge a deeply discharged battery with one.

 

Diagnosing a battery drain when parked is tedious:

 

First you need to disconnect everything that should draw current with the key off. Unless you have added accessories that's probably only the clock, if it has one.

 

Then you need to disconnect a battery lead and hook an ammeter in series with the battery. On one this old you can get away using a voltmeter.

 

Then start disconnecting things until the meter reads 0. Last thing disconnected is the problem.

 

As previously mentioned the voltage regulator is a good candidate. I believe on your Chevelle it'll be built into the alternator. I'd disconnect that first.

[mm482]

Check the voltage at the headlight bulb. I was working on a 69 Chevelle a few years back and all four of the headlight bulbs were bad.

 

Earl

[Jerry W]

I had a '73 Impala and had a problem with the headlights that turned out to be the switch to turn the headlights on. If I remember correctly, you pulled the switch out to turn the headlights on and turned it from side to side to adjust the brightness of the dash lights or turn the dome light on.

 

Anyway, the headlights were giving me some trouble and I noticed this switch was a little warm. I changed it out and all was good again.

[MiCarl]

Check the voltage at the headlight bulb. I was working on a 69 Chevelle a few years back and all four of the headlight bulbs were bad.

 

Earl

 

Yes, check the bulbs first. Should have had that in my earlier post.

 

My dad tore a house half apart once because BOTH bulbs in the bathroom burned out at the same time.

[Eck]

I had a 70 Chevelle (mine was a 6 cyl) and my headlights went out also.

 

It was a broken wire off the voltage regulator.

 

On mine:

Standing in front of of car, looking aft, and next to right hand side (drivers side) of radiator

is where I found a red wire that pulled out of its terminal lug that went to the voltage regulator.

This wire was right on top of the other wires and was very easy to see and fix.

 

I removed the lug and since I didn't have another lug at that time, I wrapped the wire around the screw, tightened it, and never had another problem with it.

Who knows..you could have the same problem..

[vic venture]

Bad headlights won't draw the battery down but something has to be. I short in the wiring would cook a wire and you would see smoke or Flame. The battery acc wire goes directly to a relay on that vehicle and the relay is activated by a wire from the switch which is also powered off the direct battery ac wire. neither goes through the acc on the ignition switch, Get on a forum and get the wiring diagram for that vehicle and see if the relay is activating or if maybe there is a short in the relay oe swith. better yet, just give the car to me and you won't have to worry about it anymore. then it will be my problem!

[Sideoftheroad]

MiCarl is right in that the clock is always running. (as an fyi...) I don't have a radio, or A/C to worry about. I have had it sit for a couple months w/ the clock running and never had a starting issue. This just seems to have crept up. I replaced the battery last year because it wouldn't start and the previous battery was at least 6-7 yrs old. So figured it was time. Now since it drained the new battery (providing the new battery isn't bad) maybe the old one hadn't gone bad yet. At least the new battery is still under warranty.

 

Didn't think about what might be the obvious in that the headlight bulbs have gone out too. I have had the car for like 8 yrs now (I think). In that time I have changed the dimmer switch twice (this would make it the 3rd.) Yes it is on the floor so moisture could be the culprit. They are cheap enough.

 

What I have is a multimeter Digitek DS830B. I can do volts, guessing it is good for Ohms too. I have to look at it again.

 

And what I am gathering from everyone is by checking the volts and ohms, this is basically doing the same thing as what Autozone can do, correct? For experience on how to do it as I am electrically challenged, wouldn't hurt to do it and take the battery, alternator and maybe even the starter to see if they get the same results as I do.

 

I had the engine rebuilt maybe 4-5 yrs ago. Instead of tuning to TDC, the guy turned the mark 180 degrees. Talking about a hard start. I at least believe after a couple hard starts like that, it killed the alternator. Or could have been the original alternator and it was time to go. Yes I realize the alternator is part of the charging system and no so much as the starting system. So bought a rebuilt one and had worked for many years. It might still be good. Won't know until I test it. Being rebuilt and newer not sure if regulator is internal or not.

 

Also this is a 40 yr old car. All the wires are cracked, connections corroded, etc. lol. Just kidding (but not really). Original wire harness I am sure, but not looking to buying a new one.

 

All great advice guys. Now I just need some warmer weather to pull it out of the garage to see what's going on. Not enough room in the garage to be able to check it out.

 

Also got some other issues I have to deal w/ 1st like a leaking house roof. :-(

[MiCarl]

If I remember right those old clocks have an electromechanical winding mechanism. If the clock isn't working I'd put it high on my list of suspects.

 

Another thing to look for is chewed wires. The vermin hiding in garages often passes winter by chewing on wires.

[irydasteelhorse]

i have a 67 olds 442, had the same problem.....replaced the headlight switch, didnt help it, but the dimmer did.....and also took the ground wires off at the core support (radiator support) and cleaned em real good with a wire brush on a drill, and reattached with new screws...........all is right again

[bongobobny]

Providing both headlights didn't blow out both filiments on each bulb, my vote is for the dimmer switch being bad. You may have a separate problem with the battery draining itself...

[Sideoftheroad]

MiCarl,

Not sure about the electromechanical part, but yes it runs all the time (when the battery has juice). I have had it run for a couple months w/out starting the car and it would fire right up, so not sure the clock is really the issue.

 

Also wonder when these cars were built in the 70's what the failure rate was for the dimmer switch. I am sure they moved it to the column for some reason in newer cars.

 

I think I mentioned it in my original post (maybe not) that we do occassionally have mice so when I look for chewed wires I at least can't see any (doesn't mean it isn't there). Couple summers ago opened the hood and all this stuff started falling out. It was like winter and snow was falling. Yipee.

 

I thought I would at least pull the dimmer switch tonight or tomorrow and check it out w/ my multimeter. Also will check fuses. Those items are easy enough to get to.

[Sideoftheroad]

Suprised no one has said it yet. Where are my manners. Here are the pics.

 

Cranberry Red, Black SS stripes, Pearl interior, bench seats.

[mraf]

Sweet! Fell in love with the ad Chevrolet had with that car and paint scheme with red florescent lights under it set at nighttime. Had a 67 Chevelle convertible eons ago.

[silent67]

If you don't already have one, order a repair manual for your car from Year One. Thats where I got mine for my 67 SS Impala. It is a copy of the original factory manual. You should be able to narrow your problem down with that.