Hi, thanks for accepting me to the forum.
I have a question that I would like some advice with.
I am modifying a Hella Intellivision module for cornering lights and want to keep the number of wires down that need to pass through the bulkhead.
I have already externalised the gyro module to a smaller unit to fit on the internal vehicle bulkhead (its a Land Rover Defender with very limited space) and am ready to commence installation and I don't want to blow the module!
The two front fog lights are connected by a 4 way multi plug. The indicator lights (used as turn sensors) are connected with another multiplug.
My assumption - there is no need to run 4 separate -ve wires.
Why do I want to do this? Because a clump of 8 power wires is substantial in this install. 4 or 5 is a signifcant reduction.
How can I validate this assumption or am I mad to try?
Investigation shows that there is zero resistance between the -ve wire connection points on the multiplugs.
Fundamental question is - can I connect all to one -ve to go through the bulkhead and/or do I even need to separate them again or apss them through the bulkhead? Can I just connect to chassis which is -ve earth inside the vehicle and rely on the individual units being earthed in the engine compartment connected to chassis? They are all operating at 12v.
The manufacturer has declined to answer my emails :-(

 

I am guessing that the modules that you are using need clean power.

 

I am guessing that the modules that you are using need clean power, with no noise, and I am also guessing that what makes the most sense is to have both cameras powered while driving. I am also guessing that the battery is fairly forward, and that a battery feed is available in the big body power control and distribution block someplace under the hood. So pick up the battery positive at a fused terminal there, then run it through a single pole relay to the filter and then to the two cameras. Now you only need one thin wire to control the relay, unless you want to trigger it with the fog lights power.

Thanks for the reply. The use case is a bit different.

This is a logic controlled module which takes input from the turn signal, gyro sensor and speed signal. The logic is 'if speed is less than 40kmph AND turn signal is detected THEN switch on one fog light, at the same side as the turn indicator' then 'if the gyro does not detect turn sideways force THEN switch off that fog light'. There is further logic for speeds above 40kmph.
So it lights up the inside corner when turning or changing lane.

No cameras involved. Further the battery is under the passenger seat - it is an off road truck and capable of deep wading hence desire to keep in passenger compartment. All power distribution is inside the passenger compartment under the drivers seat! The module is permanent live via 15A fuse. Effectively the module is a (complex) logic controlled relay.

I am further considering keeping all electronics inside the passenger compartment by picking up the turn signal at the indicator stalk.

That's why I am seeking advice on sharing the negative across the various connectors.
This is a simple vehicle with Canbus only for the engine and security ECUs.

 

OK, and sorry about the wrong guesses. Not familiar with Land Rover products at all.
Now I see what the situation is, and it is totally different from the first guess.
As for Ve, I take that to be the 12 volt system negative, also tied to the vehicle frame. For this application chassis common should be entirely adequate, picking it up in the engine compartment. In fact, you could also pick up the turn signal lights wire, presuming that they also pass through the engine compartment. But that may not go along with the plans, and water-proofing connections, even to body metal, requires doing it right. So even one single frame connection should serve for all of this application , in the underhood area.
The only possible issue that I see is if the fog lights use a single feed for both, then both will illuminate for each turn.

 

I would tie the load grounds to the chassis, and bring the electronic grounds to the main source via separate wires.

 

OK, and sorry about the wrong guesses. Not familiar with Land Rover products at all.
Now I see what the situation is, and it is totally different from the first guess.
As for Ve, I take that to be the 12 volt system negative, also tied to the vehicle frame. For this application chassis common should be entirely adequate, picking it up in the engine compartment. In fact, you could also pick up the turn signal lights wire, presuming that they also pass through the engine compartment. But that may not go along with the plans, and water-proofing connections, even to body metal, requires doing it right. So even one single frame connection should serve for all of this application , in the underhood area.
The only possible issue that I see is if the fog lights use a single feed for both, then both will illuminate for each turn.

Thanks MisterBill2. Sounds like good advice and gives me the confidence to give it a go! I'll post how I get on.