Doghead relay problem; self inflicted

[dagsurplus]

I did the Doghead relay fix a few months ago; worked great. Today, I got around to putting the relay mounting plate back under the lower dash. In the process, I inadvertently grounded the 24V terminal, the one with the large red wire attached, to the dash. There were some sparks as a result. Now, I no longer have 24V at the red wire; I have 0V. I ran a 24V lead directly from the battery, attached to relay, and engine started fine. Can somebody please tell me what got destroyed by the inadvertent grounding of the 24V wire and how this should be remedied. Thanks.

 

[doghead]

Well, a quickly look at the TM and you should see clearly what should have failed(fusible link). Just follow the red wire back to the battery, like it's a road map.

Do not repair it with the batteries connected!

 

[antennaclimber]

I think DH is correct, get the handy volt meter out and see where it quits.

 

[doghead]

That schematic is from the back of the -20TM.

 

[Warthog]

But don't you need to read the first few pages of the TM 9-2320-289-20 troubleshooting section to understand how to read the diagrams and what all the wording and connector symbols mean?

 

[swbradley1]

Maybe.

 

[doghead]

Yes you do!

Or match the color or # on it.

 

[doghead]

And or, read the Sticky!

 

[dagsurplus]

Thanks to all who replied. The attached photo shows the four red wires connected to the 24V+ block. I believe the one I had the problem with is the orange one in the background; goes on the 12 gauge wire. I always thought that if a fuseable link blew, it would show more outward damage. Apparently not. Note that the blue fuseable link insulation is split but I still think the wire was conducting electricity. I replaced the fuseable links on all four wires. Thanks again people.

 

[K9Vic]

Interesting, to me that would just seem the installation just opened up over time and did not burn out. But if you replaced it and that fixed your problem guess it was no good.
I bought 12ft of the fusible link wire from Summit, it is always good to have on hand.

Note, when you do the Doghead mod, you should either heat some shrink tube around the exposed connecters, or wrap it in good electrical tape. That will prevent these issues with something ground making contact with it.

 

[MarcusOReallyus]

Thanks to all who replied. The attached photo shows the four red wires connected to the 24V+ block. I believe the one I had the problem with is the orange one in the background; goes on the 12 gauge wire. I always thought that if a fuseable link blew, it would show more outward damage. Apparently not.

Not. Sometimes they are obviously fried, sometimes they look perfectly fine. That's why we have test lights and volt meters.

 

[forest522]

Indeed, how did the world get by before voltmeters...

 

[MarcusOReallyus]

Well, since voltmeters are as old as our use of electricity, I'd say the world got by without voltmeters by not using electricity.

 

[doghead]

I occasionally wonder how we ate meat, before fire was "invented".

 

[760gamemaster]

Note, when you do the Doghead mod, you should either heat some shrink tube around the exposed connecters, or wrap it in good electrical tape. That will prevent these issues with something ground making contact with it.

This where I really like liquid electrical tape cover every thing bare with a couple coats and let dry before you reconnect the batteries and is good to go and easy to.

 

[dagsurplus]

This where I really like liquid electrical tape cover every thing bare with a couple coats and let dry before you reconnect the batteries and is good to go and easy to.

This is exactly my plan; do you see any problem in putting this liquid tape over the four bare, exposed metal/terminals in the starter replay?

 

[doghead]

It would be fine to use like that. It's done in marine environments like that.

 

[MTMUDRUNNER]

Thanks to all who replied. The attached photo shows the four red wires connected to the 24V+ block. I believe the one I had the problem with is the orange one in the background; goes on the 12 gauge wire. I always thought that if a fuseable link blew, it would show more outward damage. Apparently not. Note that the blue fuseable link insulation is split but I still think the wire was conducting electricity. I replaced the fuseable links on all four wires. Thanks again people.View attachment 405082

Dont feel like the Lone Ranger, I did the exact same thing today but I cant tell what size link it is it is all burned up and where is the best place to get it.

 

[dagsurplus]

I cut off the old link, took it to the local NAPA store, and they were able to match it. However, they did not have a big selection of gauges.

 

[doghead]

Have you disconnected your batteries yet?