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Sizing Wiring

EFI Wiring Fundamentals

Relevant Module: EFI Wiring Harness Design > Power Supply > Sizing the Wires

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Discussion and questions related to the course Motorsport Wiring Fundamentals

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I am rebuilding an oem wiring harness. Is there a tool to measure the guage or is there a schematic that gives the size of the wires in the harness? This is for a 2005 Honda Accord 2.4cyl LX Sedan

A wire stripper will usually give you an accurate idea of wire awg. If it cuts conductor, go bigger until it doesn't. If it doesn't strip then go smaller.

You could also cut some wire and use a caliper to measure diameter and refer to an American Wire Gauge standards chart.

K24, sensors are going to basically all be 22 awg (some shielded in there too), everything else will be 20 awg except for ign coil feeds, starter and maybe 12V to the injectors etc. Those can be 16 or 18 awg.

So the issue in my wiring is from the drivers door to underdash harness and possibly from the underdash to the relay control module in the engine bay. I'm experiencing the codes listed below. I'm assuming those would be 20awg (except the sensor codes)? I believe that the sensor codes are from the relay control module. Through the system we have at O'riellys I've been going through the Honda tech procedures for these issues. Everything except the sensors states it's caused by short to ground or an open wire. These issues started after a mechanic worked on the vehicle for an insurance claim. These issues started after the repair to the drivers door was made


P0113: IAT Sensor circuit high voltage

P0102: MAF sensor voltage low


B1160: Guage Control Module lost communication with Door Multiplex Control Unit (door lock switch message)

Body Electrical:

B1006: MICU lost communication with Power Window Master Switch

B1010: MICU lost communication with Power Window Master Switch

B1006 and B1010 are both the same procedure

B1058: Relay Control Module lost communication with Power Window Master Switch

Yeah the IAT and MAF codes are probably a bad MAF or sensor ground missing at the connector.

Personally I'd take the door panel off (and the door subharness connector inside the cabin) and just see if something is unplugged or damaged before committing to rewiring it. In my experience most body shops are not great about wiring repairs and usually there's a part broken that's been zip-tied/taped/glue back into place instead of replaced.

So far I have replaced the drivers door wiring harness (with used one) all door lock actuators, MICU Underdash fuse box ( this helped some with the issues), the power Master window switch ( aftermarket which could be the issue. Can't find an oem one). Physical issues present are security system not working, Key fob doesn't work ( I've had it reprogrammed to the car multiple times), drivers door always has power, and when the vehicle is on the locks cycle open twice every time I open the drivers door. I'm thinking once I replace the drivers door subharness that it will start the work properly. When opening up the drivers door I noticed that they didn't properly clip the harness in and it was able to move around freely. They also caked all of the connectors in dielectric grease. I tried to clean as much off as possible but it was squeezed through the front of the connectors all the way out the back of them. I figured that it was causing poor connection due to the high level of grease. Down below are some images of the connectors from the drivers door subharness into the door harness. The bigger connector is the female port for the 2 block connectors. I don't see damage to them although I'm not well versed in electrical.

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