CanTrol Backfeeding

FusionWolf

Member
Oct 8, 2012
504
Massachusetts
Hey all I got a bit of a conundrum.
I have a custom traffic advisor made of whelen 400 heads. I have it hooked into the traffic advisor port on the CanTrol unit however I cant get heads 4 and 6 to light. I used a power probe to check power and ground however I'm getting 12v both power and ground on the lights. I rechecked all my wiring and confirmed nothing is mixed up. Next I'm going to test the ports on the cantrol to make sure it's not outputting 12v on all ports, sadly the weather sucks outside so cant do it at the moment.
does anyone have any suggestions of what to look at or if I may have something programmed wrong? From what I'm seeing the traffic advisor output is only ground switching
Thank you all.
 

MtnMan

Member
Dec 20, 2012
1,533
Eastern PA
Try metering individual pins directly at the Cantrol TA connector while it's plugged in and operating. Each pin should swing from +12V to 0V as the corresponding lighthead is activated. If pins 4 and 6 are staying at +12 constantly, you have a couple of open switching transistors in the Cantrol unit.
 

FusionWolf

Member
Oct 8, 2012
504
Massachusetts
Try metering individual pins directly at the Cantrol TA connector while it's plugged in and operating. Each pin should swing from +12V to 0V as the corresponding lighthead is activated. If pins 4 and 6 are staying at +12 constantly, you have a couple of open switching transistors in the Cantrol unit.
Thank you. Im going to give this a try once the weather clears up
 

FusionWolf

Member
Oct 8, 2012
504
Massachusetts
Try metering individual pins directly at the Cantrol TA connector while it's plugged in and operating. Each pin should swing from +12V to 0V as the corresponding lighthead is activated. If pins 4 and 6 are staying at +12 constantly, you have a couple of open switching transistors in the Cantrol unit.
Actually question for you. Each pin should be grounding out no? The wiring diagram shows it as a negative switching unit with a common positive.
There shouldn't be a 12v signal on those at all right?
 
Oct 20, 2010
809
Rehoboth, MA
The outputs should be negative when active. If the LED's for the outputs aren't lighting up, then the outputs aren't working. Have you verified the programming?
 

FusionWolf

Member
Oct 8, 2012
504
Massachusetts
The outputs should be negative when active. If the LED's for the outputs aren't lighting up, then the outputs aren't working. Have you verified the programming?
I did verify programming and 4 out of 6 heads work

Sounds like it's programmed for a 6 head TA, not an 8 head.
Forgive my stupidity but I did because I only have 6 heads. What effect does this have vs the 8 head
 

MtnMan

Member
Dec 20, 2012
1,533
Eastern PA
Actually question for you. Each pin should be grounding out no? The wiring diagram shows it as a negative switching unit with a common positive.
There shouldn't be a 12v signal on those at all right?

+12V will feed though the lightheads when they're not grounded.
 

FusionWolf

Member
Oct 8, 2012
504
Massachusetts
That's correct, in the situation where the ground wire isn't grounded.
Ok. In that case then is it possible something is programmed wrong? I used the 6head TA option as I only have 6 heads on that TA.
Colors I used are:
Brown- drive outboard
Red- drive inboard
Orange-drive inner
Yellow- pass inner
Green-pass inboard
Blue-pass outboard
White- 12v+common
 

FusionWolf

Member
Oct 8, 2012
504
Massachusetts
According to this document: https://www.whelen.com/install/138/13869.pdf, outputs 3 (Orange) and and 6 (Blue) are not used when connecting a 6-head TA. I know you said 4 and 6 weren't working, but this seems like too much of a coincidence.
That does seem too much of a coincidence. I wonder if I messed that up there. Might have flipped a wire on one of the heads. That atleast explains why head 6 isnt working! I'll have to flip those around tomorrow see if that changes it.
You might have solved it!
 

Nolines

Member
Apr 5, 2018
1,678
Margate, FL
Send mtnman a case of beer at this address.... It's Miller time!
Don't you love when you accidentally fumble finger something without realizing it and you did program it correctly!
 
  • Like
Reactions: FusionWolf

FusionWolf

Member
Oct 8, 2012
504
Massachusetts
According to this document: https://www.whelen.com/install/138/13869.pdf, outputs 3 (Orange) and and 6 (Blue) are not used when connecting a 6-head TA. I know you said 4 and 6 weren't working, but this seems like too much of a coincidence.
You were absolutely right! TA is up and running now flawlessly. It's very odd as the Command Software says blue and orange is used on a 6 head TA but a power prob confirms they are not.
Thank you so much for you help
 
  • Like
Reactions: MtnMan

Forum Statistics

Threads
53,962
Messages
449,805
Members
19,102
Latest member
Hilux01

About Us

  • Since 1997, eLightbars has been the premier venue for all things emergency warning equipment. Discussions, classified listings, pictures, videos, chat, & more! Our staff members strive to keep the forums organized and clutter-free. All of our offerings are free-of-charge with all costs offset by banner advertising. Premium offerings are available to improve your experience.

User Menu

Secure Browsing & Transactions

eLightbars.org uses SSL to secure all traffic between our server and your browsing device. All browsing and transactions within are secured by an SSL Certificate with high-strength encryption.