Ken the electrical guy Q n A

Hi Ken and everyone!

Hope you're doing good. I've got a project that i'd like some input on if you're free.
2002 tacoma reg cab dlx. Stock electrical system.
For fun and learning, I'm installing a raspberry pi head unit in the truck along with a 7" touchscreen, various dongles, and using the openauto pro program to enable android auto as well as carplay. I have all that figured out, and it works on my desk. This will run in addition to my original stereo.

Now installing it in the vehicle, I'm not so confident about...
I'm using a latching power control/converter/supply board called carpihat, and I'm trying to wire it all up preferably without burning down my truck.
The carpihat takes constant 12v in, and uses switched 12v to trigger the on-off functions. It also converts to 5v. I'm including the pinout diagram below.

The expected draw of all the parts is likely less than 4amps at 5volts.

My question is this:

• I'll need to connect to constant 12v (like batt), ground, switched 12v+ (like accessory power), and ground.
• Do you think I can safely power this using the cd changer port in the back of the oem stereo? Or should I do something else?
• How should I fuse this?
• Open to any suggestions you have.

https://github.com/gecko242/CarPiHat

Power Supply:
The power supply features the following basic topology:



This means that the Raspberry Pi is switched on with the "Switched 12V". It then latches its own power, and looks for the "Switched 12V" to be turned off. It then performs a graceful shutdown, delatching the power supply when the CPU shuts down.

 

Hello,

I’m sure you have probably finished this project already but I figured I’d answer anyways.

Seems like you have a good set up. I would not use the constant 12v bat circuit in the trailer harnes. Your solar and inverter will do that job. You want to be cautious directly connecting batteries without some type of low/high voltage disconnect. Not to mention depending on the net voltage of the battery bank you may accidentally find yourself in a very high low volt high amp situation on a wire that wasn’t designed to carry it.
I would recommend keeping the factory wiring u touched unless you need a key on or illumination trigger.

for grounding you want to first ensure that you starter battery is grounded to the frame. I can’t express how important solid grounding is. Once you know that you have bonded the starter battery to the frame then we can work our way back to the rear. To ground the trailer battery bank you need to find a “meaty” section of the frame. I would then bond from the frame to your Anderson connector. This will serve as a break away point / disconnect. I would recommend welding cable for this. It’s flexible but a great conductor.

i hope this helps. Sorry for the late response.

 

Hey there,

sounds like a neat project. Thanks for sharing it with us.

I’d say first id find a nice location to mount my power supply. Once if found a location id probably mount it. Then I’d make myself my input and ground leads to go back to the battery. From there, we have plenty of fusing options for automotive purposes. Your basic in line fuse would serve you well for this. There’s some nice fuse blocks, fuse holders, circuit breaker but this will require mounting and possibly brackets. If you are just adding one fuse just use a inline fuse.

Personally,

I do everything in my power to not touch factory wiring. I mean how long does it really take to run two wires from the battery to the dash. To keep your factory harness virgin it’s worth it.

unless you need a key on trigger or illumination trigger this this the only time I’ll “tap” into the factory wiring.

 

Hey everyone! Sorry if I’ve been MIA lately. I’ve been working 60-80hrs a week. Hope everyone is well.

 

Random question but does anyone know if a plug like this can be repinned or reconnected? Passenger side rear abs wires pulled out of the plug and drivers side abs wires still connected. Trying to figure out how to proceed on this one.

 

yeah you can repin it. I would suggest buying a pigtail and soldering / adhesive lined heat shrinking the wires. If you don’t repin and have the tool with the correct die for the terminals there’s a lot of room for error.

 

Thanks for the tip! I got the connector out and it looks like a pain to try to repin so I'm going to do the pigtail idea.

 

No problem. If you run into road blocks hmu I’m happy to help.

 

Hey All,

I have a question regarding the Electrical connectors found in the 1st Gen Taco and the 3rd Gen 4Runner. Does anyone know were I can find the style of electrical connectors that are compatible with the OEM Toyota Connector. Do we have a guide to this somewhere.

Long story short, I'm trying to create some harness adapters for an upcoming project. This male connector (see below) plugs into a module. I need the female version of this connector body that is pin-able. Does anyone have a source of such parts? Is this style of connector proprietary to Toyota or is this just a connector style you can find off the shelf? A way to cross reference the parts would be amazing. Any information is helpful. Thanks!

 

Hi there, its so cool of you to open up this thread thank you. A quick summary of what I've got got going on here: 2000 Taco Sr5 V6 4x4 Extended Cab. Its an Automatic transmission and Im sitting just under 200K on the odometer. A while back I replaced every interior light, including all of the dash lights with red LEDs. A lot of them were burned out so I just went ahead and did them all. When I put it all back together I now have no Speedo, no tach, and no cruise control. Also a check engine light that throws the 0500 code. I replaced the VSS on the granny and still have the same problem. My brake lights also dont work nkw, the third one on the cab does work, but not the brake lights in the tails. That part could be a coincidence but I thought it was worth mentioning. I've checked the connections behind the cluster and everything seems snug and right. Could I have shorted something out or pulled a wire loose somewhere? I checked all of my fuses and everything is fine. Any ideas. Thanks in advance.

 

Hi Ken,

Not sure if this is exactly in your skillset but do you know of anyway to monitor tire pressure with stock tpms sensors on a 2nd gen where the dash doesnt tell you? Either some purchased guage or maybe an arduino project with rfid readers?

Not interested in the screw on valve cap type.

 

Hi fellas, hoping for some help here. I have a harrop E-locker in the front, and I'd like to use a CH4×4 switch to power it, but I'm not sure how to make the connection. Here's the diagrams for both ends.



If you need any more information, I'll post it up. Thanks

 

you will not use red 2. Toyota does illumination different than the ch4x4 switch allows. Green goes to ignition, red 1 to the Harrop coil, black to ground. You won’t have variable dimming but you can connect red 2 to any dark green wire for the illumination circuit. It will be illuminated with parking or headlights but not dimmable, tap off another illuminated switch for the green wire.

 

@6 gearT444E
Thank you very much

 

you’re welcome. You can see the dark green wire is at +12V when the headlight stalk is in tail or head position. The green/white is the variable ground from the rheostat dimmer, Toyota uses a variable ground and the CH4x4 switch won’t work with that setup it would need a variable positive supply for dimmable function.

 

@6 gearT444E
Could I just tap one of the wires on my rear locker, or A-TRAC switch for illumination?

 

Here’s a curve ball.

What would cause a potentiometer based system to intermittently loose range and not activate a fault of any kind?

-Heat is a significant factor.
-Manually moving the sensor through the full range when the computer is off seems to help for a drive cycle. But it slowly and intermittently loose range.

-This is not a dead spot. If you roll onto the sensor and it loses range or drops off moving past that point does not suddenly start reading again like a worm spot would. It gradually comes back into range by itself.

 

yes

 

I have a rather simple electrical question for you. I have a 2006 Toyota Taco, 2.7L 4cyl, RearWD. I'm working on determining if my cam phaser or my VVT solenoid is to blame for my issue but in doing so I'm attempting the test the wiring harness that connects to the VVT solenoid to verify that the wiring is in fact not to blame. Trying to make sure that right voltage is getting to the VVT solenoid for proper operation during driving. To do so I have used my multimeter to measure the volts at the plug which attaches to the solenoid while it is detached and with the key in the ignition turned to the "On" position. At this point what is the Voltage reading (or proper functioning range) for which I should expect or hope to see?

VVT solenoid operating voltage?

Thanks in advance for any information in regards to this question.

 

So, as I was preparing to wire this up, I realized that the E-locker diagram doesn't match the wires coming out of the Harrop switch. The blue wire is labeled ignition, yellow/red is relay and black is ground.

Is the only change: red1 goes to yellow/red, and the other 2 wires remain the same? Here is the CH4X4 diagram for reference.



Sorry about the confusion, and thanks for the help.