Which fuses to tap for SGDCHW hardwire parking?

[triops44]

My car's interior fuse box: 08 Lexus rx350


Which are some recommended fuses to tap?

 

[Street Guardian USA]

Hello, we just put together a hardwire kit user manual.

https://streetguardian.cam/support#product-manuals





The best resource is always your vehicle’s instruction manual,
however, if you no longer have the manual please use the following
websites to access a schematic of your vehicle’s fuse panel and
function of each fuse:

http://www.autogenius.info
https://fuse-box.info
http://fusesdiagram.com

 

[triops44]

Hmm, I'm still not sure which fuses would be best? Do they have to be a certain amp? Also should I avoid certain fuses?

 

[kamkar]

Fuses pertaining to airbags and such safety equipment are generally to be avoided, seat hearer defroster cabin light and so on are fair game, i normally find one of the 10 A fuses

 

[azchrisf]

The safest and most professionaly accepted way is to tap the fuse, use it as a power signal to a relay, then run a wire directly from the battery to the relay for the Ignition On wire. I'm sure this is all too complicated for you, but as kamkar said always avoid safety systems.

I would tap ECU IGN 1 or 2 for the Ignition On wire. You will need to find a circuit that is always on with the key off (get a multimeter and test both tiny little prongs on the top of the fuse - if they BOTH have voltage, it's live with the key off), or run a wire directly to the battery (best method).

Otherwise a car audio place would be the best to install it if it's too hard to figure out.

 

[wozzzzza]

The safest and most professionaly accepted way is to tap the fuse, use it as a power signal to a relay, then run a wire directly from the battery to the relay for the Ignition On wire. I'm sure this is all too complicated for you, but as kamkar said always avoid safety systems.

and dont forget you should have a diode, the correct way, across the relay coils to prevent any unwanted damages from spikes from relay de-energisation

 

[LMJ]

I have an RX but have not installed my cam yet due to time constraints. I am considering FUELOPN and one of the power outlet curcuits. If you sit in your car with the ignition off you will notice the fuel door will open so that seems to be always on.

 

[wozzzzza]

I have an RX but have not installed my cam yet due to time constraints. I am considering FUELOPN and one of the power outlet curcuits. If you sit in your car with the ignition off you will notice the fuel door will open so that seems to be always on.

how about when you get out and lock it??

 

[triops44]

So the fuse box is pretty tough location in the car its basically on top of your foot so you have to do everything looking up.

Got this from the SGDCHW thread:
RED = Accessory (switched power source that turns on with engine start)

YELLOW = Battery (unswitched constant power that's always hot)

Black = Ground (Connected to the bare metal frame of the vehicle)

So I think what I should be doing is testing the fuses to find one that reads 12v even with the car is off, and that would be the Battery+ yellow.
Then find a fuse which is off when the engine is off and on when on, which is the red.
And then ground to a bolt

Correct? Problem is either my multimeter is broken or I'm doing something wrong as none of the fuses read anything even if the car is on or off. I'm pressing the red multimeter pin to the fuse and black is on bare metal but I can't get any fuse to read 12v. How hard do you press into the little fuse hole?

 

[jokiin]

Correct?

Correct

Problem is either my multimeter is broken or I'm doing something wrong as none of the fuses read anything even if the car is on or off. I'm pressing the red multimeter pin to the fuse and black is on bare metal but I can't get any fuse to read 12v. How hard do you press into the little fuse hole?

turn ignition on, if you still can't get a reading then you have a problem with your multimeter

always a good idea to test your meter directly at the battery first to confirm anyway

 

[triops44]

My cars battery reads 12.08v but the fuses don't read anything even if the car is on. I must be doing something wrong

 

[Street Guardian USA]

My cars battery reads 12.08v but the fuses don't read anything even if the car is on. I must be doing something wrong

Are you touching your black lead to a bare metal ground point? You don't put both black and red into in each part of the fuse points. You only touch the red lead to the fuse.

 

[triops44]

Are you touching your black lead to a bare metal ground point? You don't put both black and red into in each part of the fuse points. You only touch the red lead to the fuse.

I was touching it to metal but it might have been painted metal, I'll try to find a bare metal bolt

 

[jokiin]

I was touching it to metal but it might have been painted metal, I'll try to find a bare metal bolt

the check strap (that thing that stops your door opening too far) is usually a reliable ground point

 

[triops44]

the check strap (that thing that stops your door opening too far) is usually a reliable ground point

Thanks, got it to work on a bare bolt. But now the fuses generally say 9-10v when the engine is on.

When off, the same fuses read 6-7v, and some of them are like -.30v. so I'm still a little confused. Shouldn't it be either 12 or 0.

 

[jokiin]

voltage reading will be inaccurate if your ground isn't good

 

[kamkar]

yes. it seem like it is often the ground connection people have problems with.

 

[triops44]

Got the ground sorted out. I'm thinking of using one of the power windows or fuel opener as constant, and the ECU IGN NO 1 as the switched one.

For the constant, how do you know if the fuse is truly constant or shuts off after a certain amount of time? Now that I think about it I'm pretty sure the power windows work for a few minutes after engine shutoff but stop working eventually...

 

[DT MI]

...how do you know if the fuse is truly constant or shuts off after a certain amount of time?...

'Usually' the owner's manual will list which circuits/functions will stay active after the ignition is turned off for a certain period of time or until something happens, like opening the driver's door. If it doesn't you may find that information in an on-line user forum for the specific vehicle.

 

[triops44]

'Usually' the owner's manual will list which circuits/functions will stay active after the ignition is turned off for a certain period of time or until something happens, like opening the driver's door. If it doesn't you may find that information in an on-line user forum for the specific vehicle.

Nothing in the manual and nothing on the lexus forums for this car, tried the toyota forums but they seem to have different fuse boxes generally.

I'm going to try the fuel opener for constant and possibly the power cig outlet. ECU IGN 1 fuse seems to control some saftey stuff like traction control system.

I read that the cutoff delay for things like dome lights and power windows is somehow after the fuse, so that the fuse is constantly hot but there still is a delayed cutoff to protect the battery?