TheSamba.com :: View topic - Tail lights

Wed Aug 22, 2012 8:18 pm

I picked up a buggy this weekend. It's my first buggy so please bear with me, I'm a certified newbie. As best I can tell, its a 72 motor, a 57 chassis, and a GetaWay II body.

It has four taillights, two on each side. None are working. The two outside tails are getting current when the lights are on and when the directionals are on, but they don't light up in either case. The two inner tails don't seem to be getting any current at all. The taillights are all LED. I've been searching this forum and see that LEDs can be tricky. Does anyone have any suggestions? Should I try going back to standard taillights?

Many thanks

Wed Aug 22, 2012 8:38 pm

Are the lights grounded?

Wed Aug 22, 2012 9:30 pm

Also make sure the polarity is correct. If you wire LEDs backwards, they won't light up.

Thu Aug 23, 2012 4:40 am

I've been looking for an obvious ground but can't tell for sure. Is there a standard place taillights are usually grounded? I'll try to confirm ground first and then move on to reversing wires if need be.

Thanks guys

Thu Aug 23, 2012 5:31 am

Start at the beginning. Take a voltmeter, on DC and connect the red to the wire going to the bulb and the black to a GOOD ground. If you have voltage, check red to black on the tail light housing. If you have a bad ground the first test should have 12 volts and the second not. If you have power there, try new bulbs. Clean the corrosion from inside of the socket and check the tips in the bottom. If you have no power anywhere, check the fuses, brake switch, etc.

Thu Aug 23, 2012 8:03 am

Quote: I've been looking for an obvious ground but can't tell for sure. Is there a standard place taillights are usually grounded? I'll try to confirm ground first and then move on to reversing wires if need be.

TYPICALLY most tail light assemblies ground through their own metallic housings to METALLIC fender or body of car.... Some actually have "ground" wires (typical of LEDS) ...

IF your light sockets are mount in fiberglass body they are probably insulated from any grounds ( fiberglass is a non conductor)...

Solution may simply be to add a ground wire from metallic portion of lamp socket/holder/tail light assembly to nearest "CHASSIS GROUND"....

When VOLTAGE is present and if bulbs are good but not lighting usually indicates no ground for lamp circuit...

You use the term "current present" which is actual incorrect.... The term that is more correct would be "VOLTAGE".....

CURRENT [flow] is the action of VOLTAGE pushing AMPERAGE through a RESISTANCE (Ohms Law) .... You can only have "current flow" when you have a "complete" circuit...

Dale

Thu Aug 23, 2012 2:55 pm

Thanks guys. This is great info. The lights are mounted to the fiberglass body. I'll try running a ground tonight.

Fri Aug 24, 2012 4:23 am

OK, I don't have a voltmeter but used a simple circuit tester light (assuming this will suffice?) to run the ground check outlined by Roys Big Toys. The tester lights up when connected to red and ground, and from red to black on the outer two lights. The two inner lights show no voltage in either scenario. All four appear to be strung with the same wires.

I cleaned out each of each of the connections and checked all the fuses. Is my next logical step the brake switch? Would that cause all the tails to go out?

Thanks again

Fri Aug 24, 2012 5:22 am

All tail lights out (brake, turn, running) does not indicate the need to replace the brake light switch. It can only make the brake lights not work. Most likely you have something that makes none of them work and that is almost certainly a missing ground. It's the one connection they share in common.

I'm pretty sure you need an actual ground wire from the tail lights to the frame. Tail lights will not work in a fiberglass body without a dedicated ground to each tail lamp assembly. I have a little screw into the back of each of my Mustang tail lights. I hook a wire with a ring terminal to that and the 2 ground wires (1 each tail light) connect to the frame.

Fri Aug 24, 2012 5:30 am

Thanks EVfun. These tail lights actually have a ground post. There is a white wire connected to them. I will trace that wire back and see if I can figure out where it's failing.

Fri Aug 24, 2012 6:58 am

jporter wrote: Thanks EVfun. These tail lights actually have a ground post. There is a white wire connected to them. I will trace that wire back and see if I can figure out where it's failing.

Take a temporary wire and connect it to the "ground post" and then to steel chassis or engine of buggy.... If lamps light, you are missing "common" ground to all lamps...

By the way, are you using LEDS?... White/red/black wires sure sounds like LEDS...

Dale

Fri Aug 24, 2012 7:05 am

jporter wrote: OK, I don't have a voltmeter but used a simple circuit tester light (assuming this will suffice?) to run the ground check outlined by Roys Big Toys. The tester lights up when connected to red and ground, and from red to black on the outer two lights. The two inner lights show no voltage in either scenario. All four appear to be strung with the same wires.

I cleaned out each of each of the connections and checked all the fuses. Is my next logical step the brake switch? Would that cause all the tails to go out?

Thanks again

IF you are using one of these....

When alligator clip is connected to a ground, test lamp will light when it contacts 12 volts...

When alligator clip is connected to 12 volts, test lamp will light up when it contacts ground....

You have to know if you are looking for a "ground" or "12 volts"...

Dale

Fri Aug 24, 2012 7:22 am

Hi Dale,
Yes. that's the type of tester I'm using. I bought it after seeing a few of your posts in my earlier research. The tester lights when I connect ground to red and when I connect red to black on the 2 outer tail lights. It doesn't light either way on the two inner lights.

The lights are LEDs. There is a white wire that is connected to the post labeled ground on the back of the tail lights.

thanks

Fri Aug 24, 2012 10:19 am

jporter wrote: Hi Dale,
Yes. that's the type of tester I'm using. I bought it after seeing a few of your posts in my earlier research. The tester lights when I connect ground to red and when I connect red to black on the 2 outer tail lights. It doesn't light either way on the two inner lights.

The lights are LEDs. There is a white wire that is connected to the post labeled ground on the back of the tail lights.

thanks

With test lamp clip connected to 12 volts and if you touch the white ground wire/terminal of LEDS with test probe does test lamp light...

Your description of your procedure is a little hard to comprehend...

A LED with proper ground on white wire and 12 volts applied to either red or black wire should cause LED to illuminate, if it does not it may be bad... Might be time to remove all wiring and (bench) test LEDS alone to verify they are functional... Once you know LEDs are good or bad.... Then its may be wire issues....

Dale

Sat Aug 25, 2012 8:51 am

Hmm. I've continued to work on this and it certainly seems like it's a ground issue. But the only way I can get the lights to work is if I touch the ground wire directly to the negative battery post. Any other place I try doesn't work. Not even chassis grounds that are functioning properly for the front lights. If I leave the ground wire on the battery for more than a few seconds it begins to heat up so that's not an option.

If anyone has ideas, please let me know.

Thanks

Sat Aug 25, 2012 8:57 am

jporter wrote: Hmm. I've continued to work on this and it certainly seems like it's a ground issue. But the only way I can get the lights to work is if I touch the ground wire directly to the negative battery post. Any other place I try doesn't work. Not even chassis grounds that are functioning properly for the front lights. If I leave the ground wire on the battery for more than a few seconds it begins to heat up so that's not an option.

If anyone has ideas, please let me know.

Thanks

Disconnect all the lamps and test each one individually.... Heating wires indicates a direct short (or almost direct short).... You may have a bad unit and its playing havoc with trouble shooting the rest of them.... Isolate them and eliminate any problem unit.... I would be highly suspicions of the two units you say do not work....

Dale

Sat Aug 25, 2012 10:04 am

I tested each separately last night and they aII worked. But I was using the negative battery post as ground. Any idea why I can get a ground from the battery but nowhere on the chassis? Could the ground from the battery to the chassis be bad? Would that create a situation where the chassis won't provide ground? Sorry for Al the questions. This electrical stuff it'd all new to me.

Thanks

Sat Aug 25, 2012 10:18 am

Each 'ground' location should have very good metal to metal contact. NO paint, NO grease, NO dirt, etc.
Also you should have a heavy gauge ground strap between the chassis and the engine/transaxle assembly.

A lot of times the negative cable from the battery is simply bolted to an easy to access location on the pan/
chassis, without regard to how clean the connection is. The fact that you are generating heat in the cable is
an indication that your 'grounds' are are not clean & tight.

Sat Aug 25, 2012 11:33 am

All my grounds are cleaned with sanding wheel or wire wheel till I get bright shinny silver metallic look... Kit like one below goes long way for metal surface prep for making electrical connections...

http://www.harborfreight.com/1-inch-surface-sanding-disc-kit-96785.html

All connections are protected by dielectric grease....

Same with battery cables and where they connect... Clean bright, shinny and dialectical grease...

Only draw back to grease is it holds dust & dirt. Plus side is it protects bare clean metal from oxidation (rust) by protecting bare steel (or other conductive) surfaces from oxygen, the principle cause of rust and corrosion...

All so use it to protect all my "crimp" style terminals I put on wire ends....

Dale

Mon Aug 27, 2012 4:25 am

Thanks Dale. This is great information. The chassis and engine are pretty grimy. I'm going to clean it up and work my way through the grounds. Finally got the tail lights working but ended up replacing the LEDs with regular units. This resolved my grounding problems and I'm now grounding to the chassis rather than the negative post on the battery. The same grounds that work for the regular units would not work with the LEDs. I don't know why.

I have a short in my turn signal lever. Hoping to work on that tonight.

Thanks for all your help.