Can Diodes Fail?

[dpinvidic]

Where did JSW go???
Quite a few posts on what we think happened, but it looks like he has left the building....Maybe he got it fixed.

Dan

[JSW]

Dan, I am still here and my toad lights still do not work. I replaced the crushed cable and re-connected the toad lights but nothing works. I have signal all the way back to the diodes for tail, stop, and signal lights but nothing is coming out. I went to Harbor Freight and bought the magnetic lights and mounted them on the toad so we could continue our trip. I am now in Tennessee and when I return to Texas I will try to trace the problem. I am so thankful for all the comments and suggestions. Surely something will work eventually.

[dpinvidic]

Originally Posted by JSW

Dan, I am still here and my toad lights still do not work. I replaced the crushed cable and re-connected the toad lights but nothing works. I have signal all the way back to the diodes for tail, stop, and signal lights but nothing is coming out..

Well, based on what your saying, it sounds like the diode blocks are bad.
Are both sides of the car bad?

Here is what sounds strange. each diode block contains two diodes.
So you should have at least two diode blocks minimum, and you might have 3 or 4 depending on how the tail lights were wired up.
Anything is possible, but that means all of your diodes went bad.


I suggest you first try to fix the TOAD by itself. Remove a diode block, and reconnect a brake or tail connection to see if that filament now works.
If it does, then you have proven that diode block is bad. If it is still bad, it must be a bad ground or bad bulb.


Let me ask this...DID YOU CHECK THE BULBS????
It is much more likely that there could have been some kind of voltage spike when the cable was damaged which burned out all of the bulbs.
The filaments are much more likely to burn out before a diode is damaged.


It just seems very strange that three different lighting circuits were damaged. Don't give up.

Dan

[twinboat]

If you have a VOM, (volt ohm meter ), there should be a diode check setting. ( |< ) . Put the leads on one way then the other and listen for the sound. You should only hear it one way.

[wa8yxm]

JSW..if you are checking AT THE DIODE BLOCK (not the wires running to it)

and you have 12 volts on the "Tow Vehicle" terminal but no volts on the TAIL LIGHT terminal.... Then the diodes have indeed failed.

If you are testing at the other end of the wire... Wire may have failed.

For someone else.. Tail lights,turn and stop signlals work normall when driving car so light bulbs and sockets have been tested.

JSW... Depending on your diode kit if you can swap the two input leads..See if they now work with Motor home but not when driving..This will confirm.

But if you have a "Vehicle Spcific" kit where you "Break" a connection (Unplug a plug) and plug in a multi-diode assembly you can not easily do this. I can,but not easily.

[curtsr]

As stated earlier, diodes are like check valves as they allow current to flow only in one direction, and yes they can burn out if they are shorted out due to a higher current flow than the diode is rated. Disconnect one end of the diode and use a multimeter to check flow through it. Set the meter for resistance and connect the wires to each side of the diode and read the meter then reverse the wires. You should have a reading in only one direction but not the other. If their is no continuity in either direction, or you have continuity in both directions, then the diode is bad. The current should flow from red (+) to black (-) if working correctly... Hope this helps...

[luvlabs]

Crushed cable, wires touching. Depending on the chassis, the leads to the 7-way connector are normally fused. So look to blown fuses on the motorhome side of things.

I'll bet you have no power to those pins on the 7-way connector.

[MSHappyCampers]

Originally Posted by JSW

In leaving a Hobby Lobby in Nacogdoches the rear end of my MH drug and crushed the cable to my toad light connector. I have replaced the cable and now I have signal through the pig tail cord to the toad and to the diodes but no lights in the back of the toad work. My question, could failed/shorted diodes stop current from getting through to my rear toad lights? The wires in the old, crushed cable were all raw and touching one another. Now I'm stuck in Tyler on my way to Tennessee. Help.

Can diodes fail! Absolutely! Any electronic component can fail!

[wa8yxm]

One other suggestion.....Find another Hobby Store

[JSW]

Don't worry, I'm never going to Hobby Lobby again in my MH! My bulbs are all good and work just fine when I'm driving the car and not connected to the MH. My connector at the rear of the MH works fine. The other end of the pigtail (at the toad) also works and has good signal. At the rear of the car I have signal before the diode blocks but nothing beyond them when I'm connected to the MH. I haven't been able to find diodes on the road. When I get back to Texas I'll replace the diodes, until them I'll be okay with the magnetic lights. Thanks again to everyone who has commented on this thread, you've given me good answers which will help me when I get back home.

[wa8yxm]

Ok, That was the specific info I needed

The diodes have clearly failed

You can replace the overpriced block or you can wire an external diode around it...Advise which you wish to do and I will link.