LED light replacement and electrical issue

**JFerg65** · 02-24-2008, 13:54

I am in the process of switching out some of the lights to LED's in my 1996 2500 suburban. I have replaced the interior ones with no issues. I have replaced the back up lights with some monster leds and no issues.

Here is where I'm running into problems. When I install the rear turn / brake and running lights - total two bulbs on each side. I get them to light up when just the turn signal is on and when I hit the brake. When I go and turn on the running lights only... the fuse blows. I put the filiament bulbs back in and change the fuse out and I'm good to go again.

I do have the hyper blinking, but that is due to the flasher unit. I have an electronic LED compatible one ready to put in if and when I get all the turn signal lights switched out.

Here is what I'm thinking at this point.
1. Since I only have the leds in some of the running light sockets it is creating some sort of imbalance that leads to the fuse going.

OK so I've only got one theory at this point......

If I can't come up with an easy fix I have some red 57 LEDS for sale (RED)

Any help would be appreciated

**trbankii** · 02-25-2008, 18:09

Definitely need the LED flasher unit to have it flash properly, but all I've ever encountered is the fast flash rate - not blowing fuses... The LEDs use significantly less power, so there should be less draw and less likelihood of blowing a fuse...

Unless the flasher is going so fast it is shorting out and blowing the fuse?

In any case, I'd replace the flasher unit now. The LED flasher is supposed to work with LEDs or regular bulbs.

**JFerg65** · 02-25-2008, 19:07

That was the answer I was looking for!!! Outstanding! That will be my next step. I'll throw in the new flasher and try again. Thanks

**BamaChief600** · 02-25-2008, 21:03

So how did it go? I love LED's as a trucker we love chicken lights!!!
When we got our new Fire engine built we had all LED turns and stops and the new rescue truck we have being built will have all LEDs and LED light bar and emergency lighting.

**DA BIG ONE** · 02-26-2008, 04:22

Originally Posted by BamaChief600

So how did it go? I love LED's as a trucker we love chicken lights!!!
When we got our new Fire engine built we had all LED turns and stops and the new rescue truck we have being built will have all LEDs and LED light bar and emergency lighting.

Are the flashing LED's tripping traffic lights in a timely fashion, or?

**JFerg65** · 02-26-2008, 05:20

Got home too late and this morning we are in the beginnings of a winter storm, not sure when I will get to it.

I'm more excited about the interior LED's going in. I'll have better all around lighting and have less draw.

I have plans for a set of LED work lights on my rear load bar on top of my Suburban. That will turn night into day when I'm unloading all my waterfowling gear at 4:30 in the morning.

The whole LED process has been a learning experience in regard to what types of bulbs / applications are out there. Needless to say there is some real crap as well as some real nice products out there.

My advice to anyone doing this is, do your home work! Make certain the LED light (cluster) will fit into the existing housing such as a taillight.

**cwillis** · 02-28-2008, 03:10

pictures????????

**JFerg65** · 02-29-2008, 14:50

Are you serious?? What do you want pictures of?? My truck is presently under two feet of snow. But once it melts... hopefully by the end of the weekend, I could try.

**JFerg65** · 03-16-2008, 07:30

Well the snow melted enough an the temp was over thirty so back to work I went on the suburban. I have all the interior lights, including map lights, dome, and door panel lights swapped out. In the map lights I installed a red led bulb in the left hand side map light and a white one in the right side. I did this on all three sets of map lights. I also put one in the glove box light.

I was most concerned with the interior lights since those are the ones that are always on when I've got the doors open unloading gear.

On the outside, I was able to install a pair for my back up lights. This seems to be a marked improvement over stock. It was a tight fit due to the (something like 57 leds on the unit!

I also a have a pair of amber ones on the side marker / turns. I installed a LED compatible flasher unit. They now flash in sync with the other standard bulbs.

Here is where the project has come to a complete stand still. I have tried to install LED's in the stop /turn in the rear. Everytime I do this the fuse blows when I turn on the running lights. I am assuming it is due to too much current but not certain. This happened with or without the heavy duty flasher unit.

At this point I'm guessing I would have to solder in resistors in line to balance out the current. NOT GOING to happen.

If anybody has any other suggestions / fixes, I am open for ideas.

I will have 4 brand new 57 LED SUPERBRIGHT lights in red for sale. Let me know if anybody may be interested.

Up next will be the pair of rear facing LED work lights mounted on my rear load bar.

Jeff

**HillBilly2** · 03-18-2008, 04:54

You've got two separate circuits, one for the brake/turn signals and one for the running lights. brake/signals are OK. LED's are not gonna draw enough to blow fuses. Enough of a current thru them would blow them and open the circuit before the fuse would blow. It has to be something shorting with the bulbs. I know they are only supposed to be able to go in one way, but some socket/bulb combinations will allow it, not knowing how they are wired internally this might be an issue, check to verify. Only put in one side and test, then go to other side, see if you can isolate it to one side having the problem. It might be a defective bulb assy. Just some thoughts.

**JFerg65** · 03-18-2008, 16:26

Thanks, I'll have to buy a boat load of fuses for the attempt. I'll take your advice and just install one bulb at a time so I can make sure it is in correctly and powering up. It may take a while but it just might work. Thanks again for the suggestion.

**JohnC** · 03-19-2008, 08:19

Replace the fuse with a test light. If the light gets real bright the circuit is shorted.

**cwillis** · 03-19-2008, 15:29

Originally Posted by JFerg65

Everytime I do this the fuse blows when I turn on the running lights. I am assuming it is due to too much current but not certain. This happened with or without the heavy duty flasher unit.

At this point I'm guessing I would have to solder in resistors in line to balance out the current. NOT GOING to happen.
Jeff

There is no way that they draw more current than the incandescents do.

check out ohms law to figure it out.

i would take an ohmmeter to your wires without power to them and look for shorts.

**JFerg65** · 03-19-2008, 17:38

I guess I wasn't so clear on that. I realize the LEDS draw significantly less power than the incandescents do. I don't blow fuses with the standard bulbs in, just when the LEDS are in. I'm going to go bulb by bulb, since they only will power up if in the correct way. (some sort of protection for the LEDS), I hoping that when in wrong it is / acts as a short and blows the fuse. Since there is no way to tell the correct way to install, you have a 50 /50 shot at it. This is why I'm going to buy a bunch of fuses and go one at a time to see if I can get these to work.

Thanks for the help I appreciate it.

**DmaxMaverick** · 03-19-2008, 18:15

Know why they only work with the correct polarity? Don't forget the "D" part of LED. The D is for Diode. A Diode is an electrical "check valve". You can either have a defective assembly (LED's installed backward), or the assembly has been installed incorrectly. A "backward" LED will act like a closed circuit (short). That's is it's function.

Many "cheaper" LED's, and some application specific LED's are resistor-compensated to work as a direct replacement for the incandescents. The LED's use significantly less amperage, but the method of their compatibility may exceed the amperage of the incandescent counterpart. You could also have the wrong LED for that circuit compatibility. Unfortunately, if they are resistor-compensated, they will use the same amperage as the OEM's (or should, if they are properly compensated). Then, the only difference left is the "cool factor", on/off speed, and illumination output. The longevity is still questionable. LED's should last forever, but it's usually the CB and circuitry that fails quickly (poor design).

**cwillis** · 03-20-2008, 01:59

Originally Posted by DmaxMaverick

Know why they only work with the correct polarity? Don't forget the "D" part of LED. The D is for Diode. A Diode is an electrical "check valve". You can either have a defective assembly (LED's installed backward), or the assembly has been installed incorrectly. A "backward" LED will act like a closed circuit (short). That's is it's function.

Many "cheaper" LED's, and some application specific LED's are resistor-compensated to work as a direct replacement for the incandescents. The LED's use significantly less amperage, but the method of their compatibility may exceed the amperage of the incandescent counterpart. You could also have the wrong LED for that circuit compatibility. Unfortunately, if they are resistor-compensated, they will use the same amperage as the OEM's (or should, if they are properly compensated). Then, the only difference left is the "cool factor", on/off speed, and illumination output. The longevity is still questionable. LED's should last forever, but it's usually the CB and circuitry that fails quickly (poor design).

ahh, outstanding point indeed. heres what i would do. ( i am no electrical engineer either, but alot of jeep guy had this problem and this is what we did)

if your LEDs have resistors, make sure they are installed correctly. you can try to find some without them or buy some LED's on a circuit board and mount those in your lights.

install in all or some of your lights.

replace flasher with an Electronic, Variable load unit. they have them at advanced auto parts for $9

These units are not thermally actuated. the old ones work like an automatic resetting curcuit breaker.

then you should be good.

Chris

**JFerg65** · 03-20-2008, 03:52

I've got the electronic flasher unit, so I'm good to go there. The learning curve being what it is, I already have the rear led's (with the built in resistors). I don't have any problems with the two type 194 amber bulbs in my front corners. So I am really thinking when the leds are in backwards they are acting as a short. Like you, I'm no electrical engineer. I'll let you know what happens this weekend.

Thanks for the advice

**JohnC** · 03-20-2008, 07:51

LED's in backwards will not conduct at all. In addition, there must be current limiting resistors in the assemblies or they would blow fuses all the time. LED's only drop about 1 volt, so you need something ( a resistor) to handle the other 12-13 volts.

**DmaxMaverick** · 03-20-2008, 08:49

You're right, John. Open with reverse polarity.

**HillBilly2** · 03-21-2008, 03:29

Actually I was thinking more of a short in the socket kinda thing if installed backward. Your right, LED's will do nothing if backward. A lot of these LED assemblys are made in series so no resistors are used. When they are used it is to limit voltage, not amperage. There is no way LED's will carry enough amperage to blow a fuse. It has to be a short, It just has to be. Right????

Something else I would probably do would be to get a couple of jumper wires, wire in a fuse, connect to the battery and just start connecting them to the bulb and see what happens. Verify that they work properly outside of the socket.

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