BATTERY DISCONNECT SWITCH ISSUE

fredpinto

15 Year Member
Mar 9, 2012
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Just had an issue with my 65 mustang. I have a battery terminal disconnect switch installed on my battery and I went to start the car and no luck, just a little noise. What I found out was there seemed to be an issue with the green plastic topped threaded post that connects the two brass plates, allowing the car to start. I removed the white plastic between the brass plates, tightened the screw and the car started. Something was not allowing enough current to the starter. Has this been an issue with anyone? If so what might be the fix? Thank you for your help.
 
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Greeting John,
Thank you for your interest in my issue. I have attached a picture of the disconnect switch. You can see the white insulating piece between the two brass plates. The switch has been working for quite a while and just recently did it cause a starting issue. I have removed the insulator and it works well but there must be a reason the manufacturer had included that piece so I do not feel comfortable with it removed. I am also wondering if corrosion might be an issue. That would be easily rectified with a little elbow grease on my part. I look forward to hearing your thoughts. Thanks.
 

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Hello Fred,
May I confirm the switch is installed on the Battery Negative (-) Terminal? Correct, do not remove the white insulator, an inherent part of its safe operation, Arc protection.
If corrosion is present, it’s likely your issue. A lcorrosion inhibitor spray/antioxidant will keep that controlled in the future.
Battery post washers under terminals also help fight corrosion.
I suggest removal, disassembly, Inspection & cleaning with CRC Electrical parts cleaner & a wire brush, or soak in a baking soda and water mixture.
Once clean, clean both terminals with a post cleaner brush, reassemble using liberal amounts of Battery terminal grease, IDEAL Noalox 30-026 works excellent (or small, less expensive Counter packs of Terminal Grease, found at most part stores) works there & on terminals.
Be certain the disconnect cycles 100% open or closed when opening/closing the conductivity path using a VOM. Many times the other terminal needs attention, treat them both.
Is this a MOROSO product, what MFG. created it? Just FYI, there’s problems associated with certain disconnect types such as you’re running, but seems to be MFG specific.
Hope that helps!
-John
 
I just bought one of those for another car. How it works is the white plastic is the insulator. When the green screw is tightened down in makes contact with the top plate allowing the electricity to flow through the connector. When you unscrew it the top plate is now not connected and the green screw is isolated because of the white plastic piece. I had to study it for a minute or two to figure it out.

There are a lot of very cheap knockoff versions of possibly questionable quality. I got one made by GAMMA, a US-based company. It wasn't that much more.
 
I just bought one of those for another car. How it works is the white plastic is the insulator. When the green screw is tightened down in makes contact with the top plate allowing the electricity to flow through the connector. When you unscrew it the top plate is now not connected and the green screw is isolated because of the white plastic piece. I had to study it for a minute or two to figure it out.

There are a lot of very cheap knockoff versions of possibly questionable quality. I got one made by GAMMA, a US-based company. It wasn't that much more.
Hi, I’ve seen only one of these before,
friend had issues with it, I didn’t trust that piece of thief UHMW to Isolate power. I scrap what I don’t trust, at all voltage/current levels or not.
I run, simple, positive stop rotary switches. (Similar to Pic.below). Have seen the type your running made by Moroso & a few others, I was also able to study one, the knob to Spline that held it
failed, I machined a couple of flats on the shaft, drilled & Tapped the knob with 10-32 set screws to land on the flats
& charged nothing, he put 10$ in my toolbox. Found they could be bought new for additional costs, afterwards
(Brother in law).
But, like all parts, there’s the good designs, then the “Copycats” that mass produce them with cheap components; turning a higher profit. Proof of long term usage without fail works for îme.
Years of usage of the type below are mandatory in my race class & like the rules, they’ve evolved, too.
They’re now available with a deadman’s switch which deenergize select system based on G Sensors that you locate where you desires, setup with a (+) Terminal & fusible link(s) for your needs. Can handle 300A.
I’d find the Original MFG, only because you don’t end up with a loose connection & set off a light show near your Battery. They’re the ones which went through the N.D.T. & D.Testing & repetitions over time before they became a legitimate product. Just my 2 Cents.
I wish you luck!
-John 073E94B1-15D5-4103-8FDD-D688B4FA025F.jpeg 62A71EC0-5A36-418D-850E-C16DF0C1BDD1.jpeg
 
Hello Fred,
May I confirm the switch is installed on the Battery Negative (-) Terminal? Correct, do not remove the white insulator, an inherent part of its safe operation, Arc protection.
If corrosion is present, it’s likely your issue. A lcorrosion inhibitor spray/antioxidant will keep that controlled in the future.
Battery post washers under terminals also help fight corrosion.
I suggest removal, disassembly, Inspection & cleaning with CRC Electrical parts cleaner & a wire brush, or soak in a baking soda and water mixture.
Once clean, clean both terminals with a post cleaner brush, reassemble using liberal amounts of Battery terminal grease, IDEAL Noalox 30-026 works excellent (or small, less expensive Counter packs of Terminal Grease, found at most part stores) works there & on terminals.
Be certain the disconnect cycles 100% open or closed when opening/closing the conductivity path using a VOM. Many times the other terminal needs attention, treat them both.
Is this a MOROSO product, what MFG. created it? Just FYI, there’s problems associated with certain disconnect types such as you’re running, but seems to be MFG specific.
Hope that helps!
-John
Hi John,
Sorry for the late reply, had the grand children around the last few days and it has been rather active. To answer you, yes the switch is installed on the negative terminal. I did remove the insulator but now have reinstalled it. I cleaned up the brass terminal and the screw. I have corrosion inhibitor that I have used in the past so I have sprayed the contacts with it, it is red in color. Everything is now clean and when I reinstalled everything there is no problem with starting the car. The switch is: Moroso Battery Terminal Disconnect Switch. Is this one of the switches that has a problem? If so is there one that you would recommend?

Jack
 
Hi,
No worries, I know the feeling! lol!
No- On the contrary, Moroso is one of the better disconnects. Great, you’re running the good inhibitor, down to the Color, lol! Excellent!
Should work just fine, now, I wish you the best with it. Corrosion is the enemy, glad you got that covered. Use that on any battery terminal, works great!
Any other queries, feel free to post!
Good luck!
-John
 
Hi,
No worries, I know the feeling! lol!
No- On the contrary, Moroso is one of the better disconnects. Great, you’re running the good inhibitor, down to the Color, lol! Excellent!
Should work just fine, now, I wish you the best with it. Corrosion is the enemy, glad you got that covered. Use that on any battery terminal, works great!
Any other queries, feel free to post!
Good luck!
-John
John,
Thank you so much for the information.

Jack
 
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