my EHC delete plan wiring diagram

Energy One
BadDawg Bill

BadDawg Bill

Well-Known Member
"My plan uses 20 relays , 4 diodes, a timer, some fuses and a flasher (and a bunch of labor and some wire)"

WAY too complicated my friend. You will wind up with the same mess or worse than you had. 2 relays, 2 circuit breakers and 3 small spools of wire is all you need.
 
Axel

Axel

Active Member
Hi Bill,

Yes, true!!! I always like the "schema" what I found some months ago in this forum:

so ging das auch mal.jpg

It shouldn´t be a big challenge to reduce a carb. BD (almost) according to this "schematic". You just need to add a relay for the starter/decompression valves and one flasher relay for the direction indicators and use the ignition block "as it is"...

Have fun!

All the best!
Axel
 
BadDawg Bill

BadDawg Bill

Well-Known Member
That
Axel said:
Hi Bill,

Yes, true!!! I always like the "schema" what I found some months ago in this forum:

View attachment 36527

It shouldn´t be a big challenge to reduce a carb. BD (almost) according to this "schematic". You just need to add a relay for the starter/decompression valves and one flasher relay for the direction indicators and use the ignition block "as it is"...

Have fun!

All the best!
Axel
Click to expand...
That's the ticket. You can also add a Badland blinker module and make it very easy....
 
J

Jim H

New Member
bearman said:
my EHC delete plan....with wiring diagram

I have studied the wiring diagrams for both the Wire Plus WP374 and the PDM retrofit from Big Dog. I have also studied the Thunderheart ASM4250 and ASM4260 (another option that some may not know about).
All of these EHC replacements have a computer in them just like the original EHC.
It is for this reason that I have decided to go the “total rewire” route on my Mastiff.

In preparation of the rewire I designed a wiring diagram to do away with the EHC, using the 2007 Big Dog wiring diagram as a starting point, then modifying it.

I have not installed this on my Mastiff yet but I have ordered all the parts I need and will start on it soon. I will take pics and add them when I start.

My plan uses 20 relays , 4 diodes, a timer, some fuses and a flasher (and a bunch of labor and some wire). It uses some of the original wiring, the stock Big Dog hand controls, and the stock key and ignition system. My design also uses a negative (-) command signal at the hand controls, just like stock.
Is it complicated?.... You bet it is (see below for less complicated versions). Can the average person do it?.... No, but we Big Dogs aren’t average people (or at least we know someone who isn’t). If you can follow a wiring schematic and solder a miniature relay to a printed circuit board (or know someone you can pay to do it), then you CAN do it.

The main thing is that everything should work like stock (or better) except for the headlight, even the 10 second self canceling blinkers and resuming of blinking after using the brake. My design doesn’t turn off the low beam when the high comes on, it just comes on with it so they both are on. This is illegal in most states (just the way I like it) so if you’re really worried about it you can add another relay to turn off the low beam when you turn on the High beam.
Only the starter relay and flasher is big (1 inch cube) like the ones found in a car. The other 19 relays and timer are about ½” cube, like you find on a circuit board. I plan on mounting them on one or two generic circuit boards from Radio Shack. I bought relays with a vibration rating of 6G (gravity) to 30,000 vibrations per minute, and a shock rating of 30G. I don’t know if they will hold up or not, but I mean to find out. The fuse ratings may need adjusting if any of them keep blowing, just be careful with them.

I have decided to put my design here for anyone who wants to see or use it. I did not use standard electronic symbols for everything but they should be self explanatory to someone who can read an electrical schematic.


I see several people on the forum here have dead Dogs with a bad EHC, and have a 5 or 6 week wait on a Wire Plus or a PDM.
The 3 position key designs are less complicated and could be even simpler if you leave out the horn and blinkers (and simpler still if you just wire the key to the low beam and do not use the high beam). These simpler designs use a positive (+) signal at the hand controls.
RESIST THE URGE TO USE THE BIG AUTOMOTIVE TYPE RELAYS FOR ALL OF THE RELAYS, THEY WILL BURN OUT THE HAND CONTROLS. You must only use the hand controls to power something that draws less than 1-1/4 watts (100mA @12v), the big car type relays draw about 2 watts, so you must operate the car type starter relay with a smaller relay.

Hopefully these will be of help to someone. Maybe one of them will get someone back on the road till their Wire Plus or PDM can come in.

These I offer for use at no charge to all the other Big Dog owners of the world, but use at your own risk, I take no responsibility for you not knowing the consequences of your own actions. I can email the larger size pdf’s (750kb) of the diagrams if you private message me your email.

Good luck
bear
Click to expand...
I just picked up an 04 Mastiff that has the typical electrical issues. I looked over your schematics, nice work I must say! Question I have for you, did you ever pull the original EHC apart to see what actually failed? I came across a Federal recall suggesting that there is a pin connection failure, however I am somewhat skeptical as you should be able to wiggle it and see if it powers up the failed system. With that being said, I am wondering if there is a replaceable component within the module - I wonder if there's a cheap Chinese diode or resistor, or even something that corroded?
 
Mickmorris

Mickmorris

Well Known Member
Supporting Member
Welcome to the Dog Pound. Yeah when the EHC is shot…..it’s SHOT. Curtis @ WSW had a couple of those EHC still in stock back in March. Hope you can still get one from him. Very user friendly setup.
 
HMAN

HMAN

I just like my Freedom
Welcome from Kansas. Start a New thread and describe the "typical electrical issues" in detail. Anything electrical on these bikes is ALWAYS the ehc even tho the problem lies elsewhere. Do some troubleshooting and keep us posted with the findings. LOTS of knowledge here.
 
Axel

Axel

Active Member
Nice Job :)

If you use a headlight relay with 3 contacts what toggle between low - and high beam then you have solved the problem with low and high beam at the same time. I also have changed the starter circuit against a relay in my EHC what looks more reliable compare to a silicon chip...

All the best!
Axel
 
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