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Diodes for boost switch

February 13, 2024, 05:57:05 pm

Does anyone know the value of the diodes that were wired into the boost switch on a 91 GV300? Specifically the ones at the top of this schematic. I've found that mine have been replaced with 30a fuses. This has been providing a link between the house and chassis batteries.  I'd like to replace them with diodes, I'm just not sure what the current rating should be. It should just be the load from energizing the boost solenoid, if anyone knows what that load would be.

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Re: Diodes for boost switch

Reply #1 – February 13, 2024, 06:17:15 pm

Funny - I've looked at that schematic (for our coach) probably hundreds of times and never noticed (or took note of) those little symbols.  Where did you actually locate the fuses that replaced the diodes?

I need to look and see what I've got there on our coach.

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Re: Diodes for boost switch

Reply #2 – February 13, 2024, 06:36:46 pm

Patched in under the dash in the black and purple wires going into the boost switch.  I can only guess that the original diodes were there.

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Re: Diodes for boost switch

Reply #3 – February 13, 2024, 07:30:39 pm

I'll check that area on our coach tomorrow - see what's there.

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Re: Diodes for boost switch

Reply #4 – February 14, 2024, 12:13:12 am

I have diodes on my boost switch.
 I will look tomorrow and see if I can determine their values.

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Re: Diodes for boost switch

Reply #5 – February 14, 2024, 01:06:22 pm

These diodes allow the boost relay to be powered from either the house battery or chassis battery in case one is dead. Yes, not good to have fuses there connecting the battery banks.

Here is the Cole Hersee solenoid data sheet, the 200 amp model (most likely what you have) has a coil resistance of 17.5 ohms, this would be a current of 0.69 amps at 12V. Commonly available 2 or 3 amp diodes should work fine.

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Re: Diodes for boost switch

Reply #6 – February 14, 2024, 03:54:19 pm

Diodes, Boost switch
My 96 U320 Diodes are NTE5812's

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Re: Diodes for boost switch

Reply #7 – February 15, 2024, 07:12:57 am

Thanks! This is all great and I'll get the diodes replace. I noticed that my inverter was charging both sets of batteries. I thought I had a battery cable in the wrong spot, but turns out it was tied together with these two fuses.

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