Solving Electrical Problems Acura Vigor

[EricTheCarGuy]

After taking the dash out of the Vigor to replace the blower motor I ran into some issues. Funny thing is, the connectors I switched never needed to be disconnected in the first place. It sucks when you cause your own problems sometimes. Comments welcome.

Topic

[Russell Sawyer]

Excellent video Eric, you make that fix look easy. Looking for a voltage drop across the fuse isn’t something I would have thought of.

🙂

[none]

I always cringe having to try and access fuse blocks under dash boards like that. Fat guys just don’t fit in there very well.

[EricTheCarGuy]

For those that say it was the fuse. Unfortunately I didn’t put this in the video, but the first thing I tried was a new fuse. I got the same result you see in the video. I have run into similar issues to this in the past with a voltage drop across a fuse like this and the cause was the integrated control unit. I’ve also had issues with some Honda fuse boxes having a poor connection at the fuse itself. I’ll admit that I didn’t check for that, but I don’t think that was the cause in this instance.

[John Hugon]

poor connection at the fuse itself

That’s what I was thinking. Big problem with GM cars also…Fords you have to use pliers to remove the fuse.
[i][u]
Excellent video; you do very good work!!![/u][/i]

[dave1645]

Hi Eric
Just watched your electrical video , and Being an electronics Tech and seeing a voltage drop like
that leads me to believe that the problem, was the fuse itself..I have seen this many many times in my career , where you replaced the fuse and still nothing works, check the fuse with an ohm
meter, and sure enough the fuse seems to be fine…turns out that the fuse itself has a weak connection inside and the end. cause a voltage drop or high resistance on the out side of the fuse…Too bad you couldn’t find that fuse and try it in the car… Just a thought to help others

[EricTheCarGuy]

[quote=”dave1645″ post=114045]Hi Eric
Just watched your electrical video , and Being an electronics Tech and seeing a voltage drop like
that leads me to believe that the problem, was the fuse itself..I have seen this many many times in my career , where you replaced the fuse and still nothing works, check the fuse with an ohm
meter, and sure enough the fuse seems to be fine…turns out that the fuse itself has a weak connection inside and the end. cause a voltage drop or high resistance on the out side of the fuse…Too bad you couldn’t find that fuse and try it in the car… Just a thought to help others[/quote]

I’ve seen it too but that wasn’t the case here. I had replaced the fuse prior to shooting. I wish I would have shown that the voltage drop was still there if the fuse was not installed. I’ve seen this same issue in the past caused by the integrated control unit.

This video was something of an afterthought and there was time between me diagnosing the problem and when the fuse box was shipped. During that time I had forgotten about some of the things I did in my initial diagnosis off camera.

I’m certain that the issue was inside the fuse box. I just wish I would have made that more clear in the video.

[Rereonehundred]

[quote=”EricTheCarGuy” post=114084][quote=”dave1645″ post=114045]Hi Eric
Just watched your electrical video , and Being an electronics Tech and seeing a voltage drop like
that leads me to believe that the problem, was the fuse itself..I have seen this many many times in my career , where you replaced the fuse and still nothing works, check the fuse with an ohm
meter, and sure enough the fuse seems to be fine…turns out that the fuse itself has a weak connection inside and the end. cause a voltage drop or high resistance on the out side of the fuse…Too bad you couldn’t find that fuse and try it in the car… Just a thought to help others[/quote]

I’ve seen it too but that wasn’t the case here. I had replaced the fuse prior to shooting. I wish I would have shown that the voltage drop was still there if the fuse was not installed. I’ve seen this same issue in the past caused by the integrated control unit.

This video was something of an afterthought and there was time between me diagnosing the problem and when the fuse box was shipped. During that time I had forgotten about some of the things I did in my initial diagnosis off camera.

I’m certain that the issue was inside the fuse box. I just wish I would have made that more clear in the video.[/quote]

Help me with this question, please.

When you are measuring the voltage drop across a fuse that is in the circuit, what are you really measuring? Are you measuring the voltage drop across the fuse? Are you measuring the voltage drop across the “balance of the circuit”? Or both?

Sounds like Dave1645 should help with my questions.

[Paul]

[quote=”Rereonehundred” post=114096]When you are measuring the voltage drop across a fuse that is in the circuit, what are you really measuring? Are you measuring the voltage drop across the fuse? Are you measuring the voltage drop across the “balance of the circuit”? Or both? [/quote]

The textbook answer: Tvoltage drop across the fuse (~1V in the video) indicates that current is flowing through the entire circuit, whether that is a good thing or not. If you know the resistance of the fuse, you can calculate the amount of current flowing through the fuse via Ohm’s Law, and vice versa.

The resistance of a good fuse should be well under an Ohm, so a 1V drop would mean a fair amount of current is flowing through the circuit. Alternatively, the resistance created by a faulty fuse or a poor connection between the fuse and PCB would yield a higher than expected voltage drop.

I asked the electronics guru at work about discoloration in the copper trace on the PCB, and he said that it could be a sympton of overheating, which could create problems for components further down the circuit.

[twiggy]

I couldn’t see exactly where you were placing the probe of the meter, but the resistance of the 7.5A fuse when I looked up the data sheet is 0.011 ohms, which makes it impossible to have 1V of voltage drop across it without blowing it. But with the sum of the fuse resistance and fuse connector resistance I suppose it’s possible that you had several amps across it to give you that voltage drop without blowing the fuse. I am wondering if you had a short in the wiring harness that plugs into the back of the fuse block where you cured the short simply by wriggling and disturbing the harness.

It’s too late to do this now, but it would have been an interesting test if you put your DMM in amp mode, remove the fuse, then insert your meter in place of the fuse to measure the current that I suspect was there.

[EricTheCarGuy]

[quote=”twiggy02919″ post=114124]I couldn’t see exactly where you were placing the probe of the meter, but the resistance of the 7.5A fuse when I looked up the data sheet is 0.011 ohms, which makes it impossible to have 1V of voltage drop across it without blowing it. But with the sum of the fuse resistance and fuse connector resistance I suppose it’s possible that you had several amps across it to give you that voltage drop without blowing the fuse. I am wondering if you had a short in the wiring harness that plugs into the back of the fuse block where you cured the short simply by wriggling and disturbing the harness.

It’s too late to do this now, but it would have been an interesting test if you put your DMM in amp mode, remove the fuse, then insert your meter in place of the fuse to measure the current that I suspect was there.[/quote]

I actually did that during my initial diagnosis and got the same readings. That said, I believe the real issue here is the video I made. I should have been more diligent in my documentation of my diagnosis. Unfortunately I had already diagnosed the problem and forgot to bring the audience along.

Thanks for your input.

[Author]

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