10.6v at the rear lighting harness

The stock systems

Moderator: F9K9

plantone
Crew
Crew
Posts: 68
Joined: Tue Jul 19, 2016 10:11 pm
Location: Oakland County, MI

10.6v at the rear lighting harness

Post by plantone »

so i was farting around today, working on retrofitting my truck to some LED's, including some ribbon lights along the inside roof of the bed topper.

wired them in and when i flipped the switch.. notta

get out my trusty multimeter... 10.6 v at the light housing. Traced back to the harness where it connects, 10.6 volts there. Its drawing power from the running lights.

is this normal? or am i getting some kind of voltage drop somewhere? i thought all this stuff was straight 12v all the way across....




please help!
"Politics: The art of appearing candid and completely open while concealing as much as possible." - Frank Herbert

"Your mother was a hamster, and your father smelt of elderberries" - The French Fellows
--------------------------------------------------------------------------------------------------

'03 LS Crew Cab
User avatar
HenryJ
Admin K Elite
Admin K Elite
Posts: 12705
Joined: Tue Oct 01, 2002 9:14 pm
Location: Ontario, Oregon
Contact:

Re: 10.6v at the rear lighting harness

Post by HenryJ »

Do you have 12v at the battery? At the alternator? In the electrical center?
Suspect a bad ground if the rest of the stuff checks out good.

"Speed doesn't kill, suddenly becoming stationary does." - Richard Hammond
"Speed is just a matter of Money - How fast do YOU want to go?"-Mechanic from Mad Max-
If at first you don't succeed - Don't take up Skydiving!
- ThunderII KE7CSK
LoneWolf04
Crew Elite
Crew Elite
Posts: 238
Joined: Sun Dec 19, 2010 9:18 pm
Location: Grand Blanc, MI

Re: 10.6v at the rear lighting harness

Post by LoneWolf04 »

Second the bad ground. Check the one in the rear frame rail.
plantone
Crew
Crew
Posts: 68
Joined: Tue Jul 19, 2016 10:11 pm
Location: Oakland County, MI

Re: 10.6v at the rear lighting harness

Post by plantone »

so then i *should* have 12v there as well eh? my test at the harness connector was on the ground wire and the running lights as mentioned.

ill have to do some more testing tomorrow and check the T in the harness where the feed to the topper connects to and then work my way forward.

the battery is relatively new, but i haven't bothered to meter anything else... as i said, i just found this out when i tried to turn on the LED's and got nothing on them.
"Politics: The art of appearing candid and completely open while concealing as much as possible." - Frank Herbert

"Your mother was a hamster, and your father smelt of elderberries" - The French Fellows
--------------------------------------------------------------------------------------------------

'03 LS Crew Cab
User avatar
HenryJ
Admin K Elite
Admin K Elite
Posts: 12705
Joined: Tue Oct 01, 2002 9:14 pm
Location: Ontario, Oregon
Contact:

Re: 10.6v at the rear lighting harness

Post by HenryJ »

I am sure that you know polarity is important for LED. They won't work backward :) + has to be +

"Speed doesn't kill, suddenly becoming stationary does." - Richard Hammond
"Speed is just a matter of Money - How fast do YOU want to go?"-Mechanic from Mad Max-
If at first you don't succeed - Don't take up Skydiving!
- ThunderII KE7CSK
plantone
Crew
Crew
Posts: 68
Joined: Tue Jul 19, 2016 10:11 pm
Location: Oakland County, MI

Re: 10.6v at the rear lighting harness

Post by plantone »

HenryJ wrote:I am sure that you know polarity is important for LED. They won't work backward :) + has to be +

yes, i'm aware of that. i also tested the strand on an independant confirmed power source so i know they work.

ive been swamped the last couple weeks and havent had a chance to chase the voltage drop issue yet. hopefully later this evening i'll have time. i'm waiting on an emergency work order right now so i have to fly across town in a bit and then i'll get to play with the truck when i get back.
"Politics: The art of appearing candid and completely open while concealing as much as possible." - Frank Herbert

"Your mother was a hamster, and your father smelt of elderberries" - The French Fellows
--------------------------------------------------------------------------------------------------

'03 LS Crew Cab