Reverse sense wire....where is it?

[serug]

Hello all. hope i have the right forum. just installed a pioneer avic-x940bt in my 2010 aveo with a backup cam. the cam is acting up. it doesn't come on sometimes and most of the time it only works when i first turn the car on. i read on the forum when i first had an issue to tie the violet wire to one of the backup lights. i did that, but i'm still having issues. i need to find the reverse sense wire on the car. i searched the forum and internet for other options. the only choice i have now is to ask. does anyone know where it is? color and location? any help would be appreciated.

[petrified.rabbit]

that sounds more like a ground issue than the signal wire.

the reverse light is probably the closest to the camera that is a reliable source, i would say check your connections.

[serug]

thanks for the reply. the camera is connected to the reverse light. it's a good connection. the problem is that when i turn on the car, the backup camera comes on. it's only supposed to come on when i put the car in the reverse gear. someone with a similar issue wrote and said that he fixed the problem by connecting the 'reverse sense wire', a voilet and white wire that is on the head unit, to the wire for the electrical reverse line. trouble is, i have no idea where to find it. i have some idea, but nothing concrete.

[serug]

i know double posting is frowned upon, but i'm not getting the response i was hoping for here. is it okay to repost on another sub-forum?

[serug]

i think I found what the problem is. I have the reverse sense wire connected to one of my backup lights. my head unit senses the reverse light because when I turn on the car, the reverse lights flash for about a half second. I guess that's enough to trigger the head unit into thinking it's in reverse. so, is there anyway to delay the current going to the backup camera like putting a capacitor and transistor inline before the camera? has anyone tried this? let me know.

[AveoJunk]

i think I found what the problem is. I have the reverse sense wire connected to one of my backup lights. my head unit senses the reverse light because when I turn on the car, the reverse lights flash for about a half second. I guess that's enough to trigger the head unit into thinking it's in reverse. so, is there anyway to delay the current going to the backup camera like putting a capacitor and transistor inline before the camera? has anyone tried this? let me know.

You seem very confused and a little all over the place.

First what make/model is the HU and the BU camera?

Generally three (4 if you count the video signal wire) wires will be associated with this. The camera will have a +12V and ground, as well as video out. You can connect the ground to ground (duh) and the +12V can be a constant (IGN switched) or use a reverse light +, some HU allow switching to the BU cam without being in reverse for like trailering and such, so you may want switched constant depending on HU and use.

The other wire is from the HU, and this would be what you are calling a reverse sense wire, when +12V is applied to this wire, it signals the HU to switch to the BU cam. This is usually what is tapped into the reverse light wire in the kick panel.

If wired correctly there is no need for a "delay". And you scare me with your options, a capacitor is used to store a charge and a transistor is usually used to amplify a signal. A diaode would isolate the current to one direction, but you don't want that either. A resistor will reduce current flow, also not what you want.

Just wire it correctly. Also, always, always, always test the line to confirm it is what you want before you tap. Also use a DMM, not a stab light.

[serug]

thanks for response. Hu is a pioneer avic-940bt. the camera is some cheap thing made by ouku, I think. anyway. I have everything connected right. I have the video coming from the camera going to the video port on the HU. I have the 12+ and the gnd going to the backup lamp's +12v and gnd for pwr. and I have the 'sense' line from the HU also going to the backup lamp+12v . the problem is that when I turn on the car, the HU sees a signal from the 'sense' line because when the car starts I can see the reverse (backup) lights flash very briefly. when the HU sees that it has a positive signal before the HU fully starts, the HU will show the backup cam screen and will not disengage it until I press a button. then, it will not automatically come on when I put it into reverse. I need to stop the HU from seeing the positive signal on the 'sense' line before I put the car in reverse or at least until the HU fully starts. that's what the cap and transistor is for. just to slow down the current and buy enough time to let the HU start up. does that make sense?

[AveoJunk]

I need to stop the HU from seeing the positive signal on the 'sense' line before I put the car in reverse or at least until the HU fully starts. that's what the cap and transistor is for. just to slow down the current and buy enough time to let the HU start up. does that make sense?

Well if it is working properly the HU should switch back to normal display when there is no +12V on the "reverse light" line. That would be normal. You start the car, put it in reverse, it switches to cam, then when in drive it switched back cause no +12V. So even if there is a momentary +12V on the line it should switch right back to display mode.

Try verifying the reverse light wire you tapped with a digital multi meter. hook it up and start the car. Look to see the voltage and then see if it goes to 0. Then place the car in reverse and see if it goes to and holds +12V. Then put it in park and see if back to zero.

[AveoJunk]

Hu is a pioneer avic-940bt. the camera is some cheap thing made by ouku, I have the 12+ and the gnd going to the backup lamp's +12v and gnd for pwr. and I have the 'sense' line from the HU also going to the backup lamp+12v .

Another thing, I would connect the +12V for the power input of the cam to another power source, a switched +12V, not the reverse light wire. This would also allow you to switch to viewing the camera manually if trailering. I looked at the install manual but not the users manual, there may be some settings in the HU for tha camera. check that as well.

Nice HU BTW. Good luck

[serug]

okay, I fixed the issue. turns out, for some reason I can't understand, that when the car is on, started and/or in acc., there is a constant +12v on the positive line for the backup lights. even when the car is not in reverse. when you put it in reverse, the voltage drops to ~11.23. funny thing is that the negative line also has a constant +12v even when the car is not in reverse, but when you do put it into reverse the negative line voltage drops to ~1v. so, I just connected the sense wire to the negative and set the HU to sense a GND instead of BATTERY. Thank you guys for the help. thumbs up to AveoJunk. I appreciate it!