Need to tap into a +5V wire at the ECU, car is ODB1.
What wire will supply this?

 

The ECU isn't a power supply. Pretty much any wire that has 5 volts on it is feeding a sensor. Tapping that line will muck up what the ECU sees off that sensor and could cause driveability problems.

What is it you are trying to achieve?

 

you can use the 5V from the datalogging port, Thats the only one I can think of.

But it will be best to make a 12 to 5V inverter or just pull apart a cig ligher phone charger.

 

I'm hooking up a Modifry ECT converter to run the coolant gauge in my S2000 cluster.
IT NEEDS +5V, 12 will fry it.

 

yea you need a dc to dc power adapter, when dealing with computers (5v) as stated above its for signal or sensors, granted its 5v but the usually after 500ma-2a on some you will initiate some "ummm toastyness!" just make sure when you get your converter you check the max amp rating on it to ensure you have a safe setup.

 

I tapped my CRX ECU at location C13 which is a yellow/white wire. To get power to the modifry unit. This is the wire which sends a +5V to the modifry unit. Remember not to connect any other power wire higher than a +5v to the Modifry unit. If you do it will damage/fry the Modifry unit. This is for a Honda CRX and the +5V will be different on other cars.