New Head Unit Causes Fuse To Blow

[cstanfield13]

I recently purchased the Pioneer AVH-4400BH from Crutchfield and installed it in my 2008 Honda Accord LX-P. From what I know, I have installed it correctly using a wiring harness and a parking brake bypass. However, each time I turn the car on, the 7.5A fuse that controls the dash illumination blows. It has blown 3 fuses almost instantly so I know something must be wrong. The headunit works flawlessly so I am not sure what is wrong. Any suggestions would be of great help!

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[goingdef 10+ year member]

Is it possible you may have damaged some wiring further in the dash, did you tug on anything to access the plugs for your harness? Thats all I can think of since you didn't splice into anything and the HU is working, that or just a poorly timed coincidence?

 

[cstanfield13]

Could it be possible that the head unit is drawing too much power to brighten the screen, causing the fuse to blow?

 

[vaiboy 10+ year member]

It sounds like the illumination wire (orange/white) from the head unit isn't connected to the correct wire in the harness, or the orange wire in the harness is shorting to something in the dash. Since normally installing a harnesses is just matching colors, I would start with checking the orange wire for any exposed copper which could be shorting. The wire should be loose so just tape it up and try to power up it up. If the fuse blows again disconnect the orange/white wire from the harness and power it up. If the fuse doesn't blow with the wire disconnected you can leave it disconnected or try connecting the orange/white from the radio to the orange in the harness and try again.

 

[CrossoverOre 10+ year member]

ive seen a lot of honda's have that problem. I usually put a 10a in its place.

 

[goingdef 10+ year member]

ive seen a lot of honda's have that problem. I usually put a 10a in its place.

Never over fuse to solve a problem, that's how fires start!

 

[whitedragon551 5,000+ posts]

ive seen a lot of honda's have that problem. I usually put a 10a in its place.

Your doing it wrong then.

Chances are its a short somewhere. Did you solder and heatshrink the harnesses like you should have? If not I would spend the time to do it right.

 

[CrossoverOre 10+ year member]

2.5a is unlikely to cause any problems. and the chances of 7.5a being enough to supply the deck with sufficient juice is also unlikely and everything else on the circuit.

 

[vaiboy 10+ year member]

2.5a is unlikely to cause any problems. and the chances of 7.5a being enough to supply the deck with sufficient juice is also unlikely and everything else on the circuit.

Aftermarket head units do not use the illumination circuit to power anything, all the "juice" for the head units lights is supplied through the 12V constant circuit. The head unit uses the illumination circuit to trigger a dimmer for the display, in other words it's a very low current draw that won't blow fuses if it is wired correctly.

 

[cstanfield13]

Thanks for all the input guys. So I pulled my head unit back out again and I realized that I have the orange/white dimmer wire connected the orange/white wire of the head unit. There is also a solid orange wire that is for illumination/dash light. Should this be connected instead? My head unit supports auto dimming so how would I hook these 3 wires up to also make sure it still auto-dims? There are no other wires to connect the dimmer to. Will I even be able to use this auto-dim feature if I connect the orange/white wire from the head unit to the orange wire of the wire harness?

 

[vaiboy 10+ year member]

Buy some spare fuses, it really sounds more like the solid orange wire is shorting and blowing the fuse. Be sure it is taped up and there is no exposed copper that could be contacting metal behind the dash, before you try anything else.

 

[SplAffair 10+ year member]

I recently purchased the Pioneer AVH-4400BH from Crutchfield and installed it in my 2008 Honda Accord LX-P. From what I know, I have installed it correctly using a wiring harness and a parking brake bypass. However, each time I turn the car on, the 7.5A fuse that controls the dash illumination blows. It has blown 3 fuses almost instantly so I know something must be wrong. The headunit works flawlessly so I am not sure what is wrong. Any suggestions would be of great help!

most Hondas have this problem. My 95 civic coupe had it. It happens when you go from stock to aftermarket radios. I just simply upped my fuse from a 7.5 to a 10 amp this was the instruction I was given from 10+ honda tech . com members. Never had a problem since. ,you can always just run your own constant power from the battery and that should solve the problem as well

 

[CrossoverOre 10+ year member]

Aftermarket head units do not use the illumination circuit to power anything, all the "juice" for the head units lights is supplied through the 12V constant circuit. The head unit uses the illumination circuit to trigger a dimmer for the display, in other words it's a very low current draw that won't blow fuses if it is wired correctly.

the illumination of the dash pulls its juice from a constat source, just so happens to be the same circuit the deck constant pulls from. It overloads the circuit and pop. Real common problem.

 

[vaiboy 10+ year member]

the illumination of the dash pulls its juice from a constat source, just so happens to be the same circuit the deck constant pulls from. It overloads the circuit and pop. Real common problem.

Technically there is only one 12V constant source the battery. The question is does the head unit in the Honda get it's 12V constant through the illumination circuit. If that is really what is happening with Hondas, then the answer is not to over fuse, that fuse should be bypassed. In other words run the 12V constant straight from the battery, it's been a while since I bought a Pioneer but they used to supply nice long wires with fuse holders just for these situations. You don't even need to use all the wire and fuse holder, you can probably find an empty spot in the fuse panel to run a new 12V constant just for the head unit. So why would anyone suggest over fusing?

 

[JoshC 10+ year member]

Lol i dont use thoughs wires AT ALL, the illumination or dimmer orange/orange white. All i connect is main power(red), signal(yellow) and ground. But i use external amps for all my speakers. Ive never used any of the other wires and had them do anything at all. Unless maybe i had a power retractable antenna.