wiring -- Ignition module and Trans speed sensor

H

hayseed

Member
Hello... i am trying to figure out the ignition circuit on a 2007 mastiff... i have the wiring diagram -- my questions are
1. the connector with red/green/black coming from the EHC to the thunderheart has a constant 8 volts with the switch ignition key either on or off.... is this normal ? seems odd

2. there is another red/green/black connector coming from the EHC going to the tranny speed sensor,, the red wire on that switches on and off with the key and has 13 volts... i was planning on grabbing that switched hot wire to power the ignition on the new ultima motor i am installing -- does that make sense ?

i may end up rewiring the whole thing but want to get this thing started and trying to figure out a "clean" way of wiring ....

thanks in advance
 
G

ginger

New Member
need to get the wireing guide my speed and tack keep going out the back on same with lights can you help
 
W

woodbutcher

Mr. Old Fart member #145
Staff member
more info is needed. does it happen when you first start it? there was a service bulletin for this problem that re-programmed the EHC to cause it to re-cycle the speedo after it cranked but that isn't going to help you now unless you can find a BDM tech with the program to do this. could be as simple as a weak battery.
 
Th3InfamousI

Th3InfamousI

Administrator
Staff member
hayseed said:
Hello... i am trying to figure out the ignition circuit on a 2007 mastiff... i have the wiring diagram -- my questions are
1. the connector with red/green/black coming from the EHC to the thunderheart has a constant 8 volts with the switch ignition key either on or off.... is this normal ? seems odd

2. there is another red/green/black connector coming from the EHC going to the tranny speed sensor,, the red wire on that switches on and off with the key and has 13 volts... i was planning on grabbing that switched hot wire to power the ignition on the new ultima motor i am installing -- does that make sense ?

i may end up rewiring the whole thing but want to get this thing started and trying to figure out a "clean" way of wiring ....

thanks in advance
Click to expand...



Why would you use the speedo circuit to run the ignition module? :confused:
 
Last edited:
H

hayseed

Member
my ignition is powered from EHC not direct from battery... as i mentioned the lead from the EHC always had 8v on it even with the ignition switchoff / run off... when i hit the run button it would jump up to 12v -- i was hoping someone could confirm that their EHC had similar characteristics, or confirm my ehc is f'd up,,, i grabbed the speedo circuit because it was on/off with key
 
G

ginger

New Member
Starts and runs fine. When driving lights and digital speed/tack use to flicker now not working at all. Would really like wireing diagram for K9 2007 Big Dog no one in my area wants to work on it or even look at it
 
DRBarnhart

DRBarnhart

Insert title here...
hayseed said:
... the lead from the EHC always had 8v on it even with the ignition switchoff / run off... when i hit the run button it would jump up to 12v...
Click to expand...
How are you measuring the 8V? Disconnecting the module and going to pin to pin? Pin to ground? Mine reads 2.8V all the time jumping to 12V when I hit RUN measuring pin to pin with the the connector unplugged.

I don't know if you have the "optional" tach but if not there should be an unused connector hanging around somewhere. I would still use the original connection at least long enough to see what it does...

Dennis
 
DRBarnhart

DRBarnhart

Insert title here...
ginger said:
need to get the wireing guide my speed and tack keep going out the back on same with lights can you help
Click to expand...
woodbutcher said:
more info is needed. does it happen when you first start it? there was a service bulletin for this problem that re-programmed the EHC to cause it to re-cycle the speedo after it cranked but that isn't going to help you now unless you can find a BDM tech with the program to do this. could be as simple as a weak battery.
Click to expand...
ginger said:
Starts and runs fine. When driving lights and digital speed/tack use to flicker now not working at all. Would really like wireing diagram for K9 2007 Big Dog no one in my area wants to work on it or even look at it
Click to expand...
Ginger, may I suggest that you start your own thread with this problem? Or better yet, to appease the forum admin, do an introduction first? :cheers:

Dennis
 
H

hayseed

Member
thanks for the info DRB and recmomending cleaning up the thread a little - i get 8v from the EHC power lead to ground - the fact that you have some voltage there makes me feel a little better but i even question why there is even your 2.8v let alone my 8v ? -- i would think there should be nothing there until you apply power via the key switch but this EHC thing makes life a little more complicated without knowing some of the reasoning it does what it does...
 
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