New LED dash lights

[vtboy51]

I just swapped out my old original dash bulbs with some new LEDS from TBP, and when I turned the lights on and there was smoke. It was hard to tell where it was coming from. Anyone have similar problems? Maybe I jiggled an old wire and created a short.... bad regulator??

 

[jdbronco]

Do they still work after that? Do your gauges still work? Are all your fuses still good? A short or a burnt regulator would be my guess as well but if one bulb no longer works it could be that it shorted itself out somehow.
I hope you find where it came from. That magic smoke is the only way electronics can work!

 

[JaxLax]

as jd said: do any of them work?
if not, start tracing with a ammeter. up or down stream until you find where the power fails (or LED failure).
Can you remove the bulbs and bench test them to make sure they work?

 

[vtboy51]

Some additional details.
When i replaced all the LEDs (and a new gas gauge), everything seemed to be working great, except for the smoke and the blinker lights on the cluster would not turn on. The exterior blinkers did work though and I could hear the little blinker relay thing making its noise.
Once I saw the smoke I turned off the headlight switch waited a min and then tried again, smoke was back. One of the old bulbs was dead and pretty black, maybe that bulb housing is causing the problem. I'm going back in tonight to debug some more.

 

[jdbronco]

Well since it's only with the headlight switch on, I would venture to guess it has something to do with the switch or the cluster light wiring. The blinker lights should come on independently with the flashing, and not with the dash lights so I would think if they were causing it it would smoke with the lights off but blinker on.
Sounds like you got an evening on your back with a voltmeter ahead of you.

 

[vtboy51]

Anyone know what the large black wire behind the cluster goes too? The connector was pulled apart but I'm not convinced it should be able to.

 

[latrucker]

Not 100% sure but that looks like the main power feed to the fuse panel. It loops though the ammeter and needs to be linked back together somehow or protected. If not it could be a serious fire hazard.

 

[vtboy51]

Not 100% sure but that looks like the main power feed to the fuse panel. It loops though the ammeter and needs to be linked back together somehow or protected. If not it could be a serious fire hazard.

That makes sense that it's the main power supply. Once I separated the connector completely the bronco won't start. I'll replace the connectors tomorrow and see if that helps.

 

[DirtDonk]

Yep, that's exactly what it is. Not only can you tell by it's size (one of the, if not the largest wire in most of the harness) but it's Black w/yellow, which is the main charge power wire. And the fact that it runs through the ammeter loop and when it's disconnected kills power to everything confirms all the vicious rumors.

Looks like you found it at the right time too. In your garage and not on the highway!
It's supposed to look like a normal bullet/push-in connector. Yours is toast.

Since it passes ALL drain loads and ALL alternator charge loads through it, make sure when you fix it you do a good job so it does not become a choke point and future smoke hazard.

Paul

 

[September 1972]

LED bulbs are polarity sensitive and don't use much current.

The IVR and Flasher Relays work on the same principal but are designed for different voltage outputs.

When voltage is applied to the Flasher Relay the Bi-Metal strip heats up and buckles breaking the circuit. When it cools the Bi-Metal strip relaxes and re-connects the circuit.

When a light bulb is out the Flasher Relay breaks faster or slower because part of the current load for which the Flasher Relay was designed for is absent. Therefore The Flasher Relay Bi-Metal strip is heated at a different rate for which it was designed when a bulb is out.

The IVR works on the same principal with a notable difference. When 12V is applied to the IVR the Bi-Metal strip heats and cools many times per second making and breaking the circuit. The result is that the IVR will pass an average of 5V because the Bi-Metal strip will never stay connected to 12V long enough to pass 12V.

A test light with the smallest wattage 12V bulb connected in series with a sensor wire from the fuel tank or temp gauge will allow the pulse of the IVR to be observed. You may not see it with a volt meter.

There are different flashers for LED bulbs because they use so little current, the Bi-Metal strip won't get hot and break the turn light circuit.

What I would do is pig tail the LED bulbs in the external taillight and park light lenses with a dab of epoxy and use the standard bulbs then you won't have any unforeseen issues.

The LED bulbs in the instrument cluster might be the cause of your problem.

 

[vtboy51]

I'm assuming you are referring to the voltage regulator on the back of the cluster when you say IVR. I tested my IVR the other day and it was reading 7.4 volts, should I be reading the 5v you mentioned? . I've got a new one coming in today just in case this is causing my problems.

LED bulbs are polarity sensitive and don't use much current.

The IVR and Flasher Relays work on the same principal but are designed for different voltage outputs.

When voltage is applied to the Flasher Relay the Bi-Metal strip heats up and buckles breaking the circuit. When it cools the Bi-Metal strip relaxes and re-connects the circuit.

When a light bulb is out the Flasher Relay breaks faster or slower because part of the current load for which the Flasher Relay was designed for is absent. Therefore The Flasher Relay Bi-Metal strip is heated at a different rate for which it was designed when a bulb is out.

The IVR works on the same principal with a notable difference. When 12V is applied to the IVR the Bi-Metal strip heats and cools many times per second making and breaking the circuit. The result is that the IVR will pass an average of 5V because the Bi-Metal strip will never stay connected to 12V long enough to pass 12V.

A test light with the smallest wattage 12V bulb connected in series with a sensor wire from the fuel tank or temp gauge will allow the pulse of the IVR to be observed. You may not see it with a volt meter.

There are different flashers for LED bulbs because they use so little current, the Bi-Metal strip won't get hot and break the turn light circuit.

What I would do is pig tail the LED bulbs in the external taillight and park light lenses with a dab of epoxy and use the standard bulbs then you won't have any unforeseen issues.

The LED bulbs in the instrument cluster might be the cause of your problem.

 

[September 1972]

What type of voltmeter are you using? 7.4 seems high but remember it works with a load, so all your gauges should be in the circuit and the IVR is measured in series with the load.

The voltage is changing so rapidly that only the very best meters will see the voltage.

Yes, instrument voltage regulator, IVR.

 

[vtboy51]

I've got a nice Fluke. The IVR had no load on it when I measured.

What type of voltmeter are you using? 7.4 seems high but remember it works with a load, so all your gauges should be in the circuit and the IVR is measured in series with the load.

The voltage is changing so rapidly that only the very best meters will see the voltage.

Yes, instrument voltage regulator, IVR.

 

[September 1972]

Start over. Take the cluster apart and wring it out. Another way to go is to put it back the way it was leaving the fuel sender disconnected.

 

[vtboy51]

Just wanted to give an update. I fixed the main power wire splice issue, replaced the regulator, disconnected the new fuel gauge, and turned things on to find the smoking had stopped. I reconnected the gauge and the smoke was back, so now I was getting really confused. I decided to remove the new regulator and check the output voltage by connecting it directly to the battery, I got 12v, so the new one is bad. I then grabbed the old one I had originally thought was bad, and it seemed to be working when hooked to the battery.
While I was doing all this testing it dawned on me that my cluster wasn't grounded very well since it was just hanging there. I put a temporary ground on it, plugged in the old regulator, connected the gas gauge and all is good, the new LEDs even work! Is it possible the regulators won't limit the voltage if not grounded, I believe it was sending a full 12 volts to the gas gauge and that was causing the smoke. It just got real confusing with all the variables, loose main power feed, bad new regulator, etc.... Thanks everyone for all the feedback. On to the next item.

 

[September 1972]

You da man! Nice work!

I'm not sure about the IVR and why it did what it did. The Bi-Metal strips may have been fused together so when load went across it acted like a fuse link and heated up. It's hard so say with certainty. You seem bright enough to use this as an opportunity while it's fresh in your head to get the correct cause and effect of the problem.

For future reference for bench testing. I use a car battery with my old Schauer charger that put's the voltage up to 13.5 or so. The positive cable from the battery goes to the devise, the negative cable from the battery is bolted to the front of an old fender and on the rear of the fender a cable goes to the devise. I'm not sure if that's necessary but that's the way the devises will work in the field.