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Fan relays?
I like to know how things work, I was looking at the fan relays and thinking how the system works. I have a couple of 12v relays I use for Aqua Hot service and all those relays are pretty much the same except volts and amps of contacts.So they say to cut off the 85 terminal to test fans, the 85 terminal is for the electromagnet to pull contacts together, so by doing this the contacts stay in the same position. looking at the bottom of the relays I can see that the contacts are wired to the 87A terminal which is always closed position so does that mean the DDEC when the key is turned on the power is sent to the relays from the DDEC to go to the 87 terminal which breaks power , so when engine reaches 200 degrees the DDEC shuts off power so relay swing back to 87A position and it sends power from terminal 30 and fans come on, and DDEC breaks power at 2 different temps for Low & Hi speed. It just seems weird the way they did that backwards, Power from DDEC to keep fans off and no power from DDEC to make fans work. So to test fans all you would have to do is make a jumper with 2 male connectors and pull relay out and plug it in to 30 & 87A position? and either high or low would come on.??
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1 Reply
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Does anyone have schematics on this ? Got Schematics off Prevost website I see how it works now
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