MSefi.com read only forum (Jan.15,2018)

I did a few searches on here but didn't find anything relating to this so forgive me if its been covered before.

What I'm working on:

1987 Olds Cutlass Supreme
455cid engine
Derale dual 13" electric fans

MS-II in a MS-I ver2.2 board using a Relay Board as well.

I'm just now finishing up the wiring off the engine harness and pig tail to the MS ECU as well as working on the rest of the wiring for the car and was getting to the electric fan wiring.
My Derale fans came with two relays (25A each) and the fans themselves are rated at 50A for the pair. I've pretty much run out of NPT fittings in the intake to run any extra controllers and so was hoping there might be a way to control the electric fans using the Megasquirt ECU and coolant temp sensor that I have in the intake already?
Has anyone done this or can point me in the right direction on where to look in the Megamanual for information regarding this? I've gone through it a few times and haven't seen anything regarding this.

Oh, and a bit off topic but I did have another question that may be bit stupid. Does the MAP sensor for the ECU need its own signal directly from the manifold or can I tie into another manifold vacuum line? I have a total of three pieces of equipment that need vacuum to operate. My fuel pressure regulator, map sensor and my HVAC controls. The HVAC controls I was going to run through a reservoir first since my manifold vacuum might be a bit low with the camshaft I'm using. But the MAP sensor and fuel pressure regulator need to see true manifold vacuum I'm sure so my plan was to tie into the line going to the fuel pressure regulator and then run to the MAP sensor. Would this be okay?

Thanks for the help,

Sure, the MS2 can control on/off things like fans - see this link for how.

http://www.megamanual.com/ms2/spare.htm

I wouldn't share the MAP signal line with anything that uses vacuum for power, like the HVAC. Tying it in to the fuel pressure regulator is perfectly fine, though.

Thanks Matt.

Just following up with this as I'm getting closer to the actual fan wiring.

So I plan to use the Fidle port to control my electric fans but talking with a friend of mine, he thinks the two relays will be too much for the 1Amp max. He had me measure the resistance of terminals 85/86 on the relays and said if it was more than 50ohms I should be okay. The problem is that my fans require two relays. I came up with 86.4ohms between the 85/86 terminals but he said since there are two relays, that would really be 43.2ohms and would overload the transistor on the board.

He said he might be able to modify the board to handle two relays but I thought I would ask here and see if anyone has a simpler solution before we crack the board back open?

Thanks,

Easy but not-so-elegant: Ms triggers one relay which triggers 2 relays.