Jump to content

Wiring the dash switch for Blue Sea ACR


Recommended Posts

I installed my Blue Sea ML-ACR several months ago and have been very pleased with the resulting operation. My coach was not charging the chassis batteries while on shore power or house from the engine alternator. I had put off installing the BS supplied dash switch as just using the combine function a few times when starting in the cold was all I thought I really had to have. I installed two 3/4” PVC SCH 40 pipe runners thru the chassis crossmember holes when I did my FASS install to have a conduit for the new return hose. I pulled a heavy duty trailer 4 wire flat bundle from the Rear Run Panel into the Front Run Panel and then up to the side console.

A few days ago I had the dash out to see if I could get my trans temp gage to work and the switch is right there so a new project got started.

The exiting two position momentary ON switch has a CARLING VCH-01 8 style Terminal Connector Switch Base plugged into the the back. There are four female connectors plugged into the terminal base.

Double wire red for existing switch illumination, internal light power from headlight switch

Double wire white for ground used on above light

Single violet wire on terminal 2 - power from fuse 56 in FRP (pretty sure on the fuse number)

Single Violet wire on terminal 1 - switched power going to originally a Big Boy relay, now to the ACR

There are a couple of different wiring diagrams for the ACR and switch. I would suggest looking very closely for the one with a note that states the upper and lower LEDs in the ACR switch are connected together and will both be on or off as that helped me understand the wiring.

I used a thin flat screw driver to push in the tabs on the connectors in the terminal base and removed the four female connectors.   I had a few non-insulated female spade connectors left over from another project. I then made up a new 8” long jumper with a female connect on one end, a matching male spade connector on the other end and cut the wire in half to allow both wires to go into one female connector.  The female connectors on this jumper were plugged into the terminal base to attach to terminals 3 & 7 on the BS ACR wiring diagram. The wire previously connected to Terminal 2 (power from the fuse block) was attached to the male spade of this jumper to provide fused power to terminals 3 & 7.

On my original switch, the wire going to the Big Boy/ACR relay was on terminal 1, I moved it to terminal 2 of the connector base. This is connected from the switch to the ACR relay. A female connector was added to the new yellow wire and plugged into terminal 7.

The original ground white wire that was on terminal 7 was moved to terminal 1. When in the DO NOT COMBINE position of the switch,  it grounds the ACR to keep the relay from pulling in and combining the battery banks. I originally thought this was going to have to be a new wire.

The original red connector/headlight switched light power is not required for the BS ACR switch so I slide heat shrink over it. Heat shrink also insulated the violet wire power going to the jumper.

Not counting the jumper as a “pulled wire”, the only new pulled wire was the yellow from the ACR up to the new dash switch.

I thought I had taken a picture with the jumper wire between 3 & 8 in place. I could not find it. In the picture of the switch with the wires attached, the connectors are slide on the actual terminals of the BS ACR switch, not in the terminal base. The red alligator clip wire is jumping power from term 3 up to term 8. The bottom violet wire with electrical tape wrapped around it is the power wire from the fuse block.

The other picture shows how the little tab had to be flattened against the connector (red wire) so it could be pulled out the back of the terminal base.  White wire connector is were I pushed the tab back out so it would lock in. The connector seem to be available on Amazon, Baomain 1/4 inch (6.3mm) Female Spade Quick Splice Crimp Terminals, (link was really long). I may order a package, would never use 100 but for $7 they would be handy to have.

I ohmed the switch in its three positions b4 connecting wires. In the combined, rocked up position, terminals 3 & 2 are connected, sending power to the ACR from terminal 1 thru terminal 2. In the center position, both sides of the switch are open. When rocked to the DO NOT CONNECT position, terminal 2 is connected to terminal 1 which takes the relay to ground. The other observation is that terminal 7, the new yellow wire is grounding the LEDs within the switch. Any time the ACR is connecting the two battery banks, the yellow wire must be going to ground to illuminate the LEDs. Charging house bank on shore power with the ACR combined has the LEDs in the switch on.

Half way thru this project, I was not understanding what was going on. I almost just returned the switch back to the original state and lived with only the momentary switch. As I stated earlier that learning the top and bottom LED did not give a separate status for the switch helped me to understand what was going on and finish up the wiring. I was over thinking the project.

Hope this helps someone else taking this on.

HRS BS ACR switch.jpg

HRS female connector tab.jpg

  • Like 1
Link to comment
Share on other sites

  • 1 year later...

This a project that I'm planning on doing soon.  I have the switch wired up in the back and have waited for better weather to run wires from the front to the back.  The instructions below for cross connect/isolate battery banks indicate the red wire from the ML ACR harness goes to position 2 on the included switch.  The yellow goes to position 7 for the LEDs.  Power from the house side goes to position 8 and position 1 and 3 go to ground.  Does that look correct???

It appears I only need one wire from the back run up to the front (for Yellow LED) as there is an existing wire that I can use for the remote red.  Everything else can be sourced from the front?  I'm going to run several wires from the back up to the front for any future projects, so if you think the power should be sourced from the rear run box would be easy enough?  I would appreciate another set of eyes on this.  Thanks in advance.  Jim








Link to comment
Share on other sites



Sounds like you've got it. 

I actually screwed my wiring up and had to redo it, it didn't damage the switch or Bluesea. 

I wired in the isolation functions with a fuse holder, one for engine and one for generator but left the fuse out.  Haven't seen any adverse affects and I've got the option to use the dash switch to shut the Bluesee off. 

Link to comment
Share on other sites

Jim, if you have access to rear passenger side frame rail just forward of the engine, about over the bellhousing, I had a spare bundle of 8 wires in their own sleeve, rolled and tied to the other bundles there. These go all the way to the front dash with plenty of extra lenght. I found ours by chance while adjusting valves and wondering what the extra bulge was.

Link to comment
Share on other sites

I wondered about isolating the genset and the chassis engine, but I thought those instructions were more for marine applications that have two or more engines that propel the boat.  Is there a benefit to isolating the chassis and genset?

Frank had said that same thing Ivan,  I'm going to check and see if they are there, before running new wires.  If they are there...  I've got 7 50ft rolls of wire that I'm not going to need.  LOL.  I think he also said that there is a conduit?  I've also got the FASS install to do and may need some additional fuel lines run.  The next nice day that I have free to devote, I'm going to jack up the coach again and do the air dryer and check for the spare wires or run the new ones.  Thanks for the great help as usual!!!

Link to comment
Share on other sites

So, I poked my head under the coach this afternoon.  I found a big bundle of zip tied wires in front of the rear axle on the passenger side and thought I'd found the spares.  All of them went to air system components...  Couldn't find any other bundle of wires there.  Behind the front axle I found what I think is conduit.  Its about an inch diameter with a red cap?  I could not locate the other end of a conduit in the back, but the holes are all sprayed with some kind of insulating foam, so the conduit might be covered over by that.  I also don't see any obvious bundle of wire in the front axle area either.  I'll look around the generator and under the dash.  I'm at least encouraged to find what I think is the conduit.  Pulling wires through it should be pretty easy... at least that is what I'm telling myself.


Link to comment
Share on other sites

Maybe you don't have the bundle but mine was in this corner of the engine room. I don't think I would have found it looking for it from underneath. It ends with a coiled loop behind center of dash and I had to tone it out to locate.


Link to comment
Share on other sites

Making baby steps of progress.  I have found spare wires in the front.  Two red, two black and one smaller green.  The prior owner had wired in a brake controller and has used two of the wires... I was looking in the FRB and noticed a piece of label laying in the bottom... I picked it up and it is torn... but what is left spells  PARE.  One of the wires that the prior owner used also has a piece of the same color tape and it dawned on me... SPARE.  So, I have spare wires.  Yee Haw.  I have searched high and low in the back and cannot find the other end.  So, any suggestions on where they might have hidden those spare wires in the back? 

Also, anyone have any knowledge of how you wire up a brake controller?  Again, the prior owner tied into two of the spares... I assume those wires would be needed in the back to connect to a trailer in order for the controller to work... I checked the original trailer plug... nothing new added to it.  Any suggestions of where a controller would need to be wired up in the back?  I think I'm close.  I only need one wire to connect the switch for the Blue Sea switch. 

Link to comment
Share on other sites

Continuing to have issues.  I ran a wire from the orange wire in the rear to the orange wire on the boost switch and have no continuity.  I tried it with the ignition off and on.  Shouldn't that wire have continuity either way?  Still no luck in finding the spare wires in the back.  I did do a search for the wiring diagram for the brake controller and one of the wires has to tie directly to the 7 way trailer plug... but have not found that connection either.  I'm going to crawl back under the rear and give it another try at finding the spare wires.  I have an RF sounder, but it does not seem to work or I'm not working it correctly.  I think it gets to much interference from all the wires in close proximity.  I may see if I can find a different type of sounder.

Edit... on my coach the wire going to the big solenoid is orange and the schematic shows the orange wire running from the back up to the front boost switch.  I was hoping of using this as one of the wires that I need to wire in the BS remote switch up front... but again there is no continuity on that orange wire in the rear and the orange wire on the front boost switch.  So, there must be a break in that line somewhere? 

Edited by Just Jim
additional info.
Link to comment
Share on other sites

The orange wire is for isolation, this is if you want to disable the MLRac when there is another power source, say generator. 

The the BlueSea needs 3 wires to the switch and a jumper cable

  1. power supply which I picked up in the front,  plugged into +8 spade
  2. Yellow LED plugged into the -7
  3. Red Remote from the Blue sea which was the existing wire for the boost switch plugged into the 2 spot, in my case this was the purple wire
  4. Jumper cable between +8 & spot 3

 The Bluesea also needed a ground and  I used the existing ground coming from the ground bar.

The wire from the original boost switch, which on my coach was purple was hooked the the isolation solenoid, so I used it for the remote switch .

But I had to get a third wire from the BlueSea all the way to the front dash to wire in the switch, this is the yellow wire on the instruction.  I did search for a day for an available spare wire in the rear of my coach but couldn't find one so pulled a set of 5 wires to the front so I could use one for the switch switch. 



Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Create New...