[dhauff]

piv.. I think you mean WHT/GRN when you refer to ALTC above. Correct?

 

[Piv]

oops - I did mean ALTC is WHT/GRN on above post. Thanks for the catch.

ALT FR, WHT/RED, initial check appears to be good. Approx 5V and varied some when Emergency Flashers were on.

Thanks -Piv

 

[dhauff]

piv.. how confident are you that your meter is providing accurate readings? Hate to chase this issue around and find out you have a vom that is not very accurate.

 

[John Clark]

I'm just reading back through the first parts of this thread and I wonder if we're barking up the wrong tree here. After the answers in the first couple of posts I no longer suspected the alternator. I'm looking closer at the lights that are coming on and what isn't working. You say all four door lights come on and the windshield washers don't work. Sometimes you have to look at the simple things that aren't working. Looking at the windshield washer circuit it is pretty simple...no PCM control. It is powered by a fuse in the under dash fuse box and controlled by a module, also in the fuse box. Additionally, the door open lights are also run by a module in the under dash fuse box.

Have you looked at the under-dash fuse box? I'd pull it loose and look on the back side for any signs of water intrusion. Water intrusion and it's subsequent corrosion, will do strange things and could be causing all of this.

 

[johnboy1313]

The windshield washer does work when the problem shows itself (previous question).

I'm just reading back through the first parts of this thread and I wonder if we're barking up the wrong tree here. After the answers in the first couple of posts I no longer suspected the alternator. I'm looking closer at the lights that are coming on and what isn't working. You say all four door lights come on and the windshield washers don't work. Sometimes you have to look at the simple things that aren't working. Looking at the windshield washer circuit it is pretty simple...no PCM control. It is powered by a fuse in the under dash fuse box and controlled by a module, also in the fuse box. Additionally, the door open lights are also run by a module in the under dash fuse box.

Have you looked at the under-dash fuse box? I'd pull it loose and look on the back side for any signs of water intrusion. Water intrusion and it's subsequent corrosion, will do strange things and could be causing all of this.

He said the washer pump IS working.

 

[John Clark]

I missed that but I think I'd still check the MICU (fuse box) under the dash. It's not uncommon for water to get in and corrode things and cause weird issues. The door open indicators on the dash are what make me consider checking the back of the fuse box since the controller for them is in that MICU.

 

[dhauff]

What I have done recently:
Got a 4 lead plug from the junk yard and am providing only one input at a time. Currently have jumped the IG wire from original plug so it is the only one going to the ALT right now. Time will tell but the input IG and ALT output appears to still fluctuate a lot. However, no dash lights yet. Just did this recently so I'm going to monitor it for a while.

If you have disconnected the ALT-L wht/blu wire and run the van, I don't think you will get any battery light. The batty light comes on when the alternator produces less (or no) voltage on the ALT-L connector than it gets from the battery positive terminal. For example, if the battery has 12.5 volts and the ALT-L connector at the alternator has 11.5 (for example) current flows from the battery through the fuses, through the ign switch, through another fuse through the battery dash light and then to the ALT-L connector at the alternator. With current flowing, the light is on.
Now if the Alternator has 12.5 or more at the ALT-L output, then there is no current flowing so the light stays off. So one test would be to have the ALT-L disconnected, and the car running, what is the voltage reading on the ALT-L connector at the alternator (with no wire connected there). I think the best way to test this is with the enhanced OBD reader, leaving it connected while driving so you can monitor all the values you need on one screen.

I think its either the ELD telling the alt to stop putting out voltage or the alternator's voltage regulator failing intermittently to produce the proper voltage.

 

[Piv]

Thanks - I do have confidence in the fluctuating reading on the ALT IG wire. However, I am looking at possible getting a scopemeter like the LIUMY LM2001 to be absolutely sure. Not sure if anyone has had any experience with these scopemeters but I'm hoping this might give me the total confirmation I am looking for.

Also, at the risk of sounding bonkers, I wanted to let you know about another electrical issue I had prior to this problem. Didn't bother to say anything because it seemed totally unrelated and went away on it's own....just like it occurred. Here goes:
After starting the car (i.e. ignition switch on) the rear fan would come on high with the fan switch/s off. I discovered it would turn off only if I turned on the headlights. After turning the car off (i.e. ignition switch off) the fan would run until I turned off the lights. That problem seemed to solve itself and I mention it to be complete in letting you know other history of the car.

May sound like this car has always been a problem but not the case. With 360K miles, I guess you should expect a bump or two along the way. - piv

 

[dhauff]

HOw long have you had this van? If you bought it used, did you ever run a carfax or something to determine if was a salvage flood vehicle. Seems like are some real nasty electrical issues. Hard to see how turning on the headlights would turn the rear fan off, or why the fan would stay on with the ign off.

 

[Piv]

I know - seemed peculiar to me too. This is another reason I opted to replace the PCM....just in case.
Purchased it new. Has always run great.....just had a few other issues along the way.

 

[John Clark]

If you are sure that the fan switch in the rear was off but the rear fan was on high then the only way that can happen is if the fan circuit is given a ground somewhere. The only place the fan can get it's ground is through the switch, between the switch and the fan motor, or at the blower resistor in the rear HVAC unit. The switch is up above the driver's side sliding door.

I am more and more convinced you have a water intrusion issue. If I had to guess I'd say it's leaking in through the roof rail seams or sunroof, running into the rear fan switch, and also down into the fuse box under the dash on the driver's side. That's where I'd look next.

 

[Piv]

Thanks John - I'll take a look at it this weekend. I haven't seen any apparent leakage but it is parked outside and has endured some torrential rain....including a hurricane or two. Appreciate the help and advice.
Piv

 

[John Clark]

Especially after that comment, I would be willing to bet my lunch money you're going to find some moisture intrusion behind the driver's fuse box. I don't know how easy it is to pop it out but I'd also have a look behind the rear AC controls, as well.

 

[Piv]

PROBLEM SOLVED.......

OK. I am declaring this flashing dash light problem solved. I am almost embarrassed to say that the issue was in fact the alternator. I'm sure there are lots of "I told you sos" out there - and rightfully so. I installed an OEM alternator (3rd one but 1st OEM) I got from the junk yard for $80 and have been running for three weeks now without a problem! Before this install, I couldn't go 30 miles without the lights flashing.

What a long road to get to this fix but I certainly learned a lot along the way. For example:
Don't EVER install an aftermarket alternator from the parts house.
Be sure to totally eliminate the most obvious things first - even if you have installed a "good/new" component.
The electrical system on a Honda is a pretty awesome design.
The folks on this forum are EXCEPTIONAL.

Thanks to all for your help along the way. BIG THANKS to everyone who helped me out.

Piv

 

[dhauff]

Good to know. Thanks for the follow up.

 

[dandrew.blay]

PROBLEM SOLVED.......

OK. I am declaring this flashing dash light problem solved. I am almost embarrassed to say that the issue was in fact the alternator. I'm sure there are lots of "I told you sos" out there - and rightfully so. I installed an OEM alternator (3rd one but 1st OEM) I got from the junk yard for $80 and have been running for three weeks now without a problem! Before this install, I couldn't go 30 miles without the lights flashing.

What a long road to get to this fix but I certainly learned a lot along the way. For example:
Don't EVER install an aftermarket alternator from the parts house.
Be sure to totally eliminate the most obvious things first - even if you have installed a "good/new" component.
The electrical system on a Honda is a pretty awesome design.
The folks on this forum are EXCEPTIONAL.

Thanks to all for your help along the way. BIG THANKS to everyone who helped me out.

Piv

Wow, what a journey and thread! Similar issue but my engine stops too. 2014 Odyssey - symptoms are flickering power to all things, engine sputters, sometimes stops all together. Happened 1st approx 12 mo. ago - had alternator replaced & battery at a dealership (we were out of town). All has been good until today. Driving, all flickered, engine stopped. 4-way flashers did not even work. A min or 2 later, power returned, my 4-way flashers started to blink. Stared van as normal, drove home.

Do i need an OEM alternator? Will look thru and look at earlier suggestions too. Wondering about battery post spacers . . . Maybe bad connection. Other ideas?

(5ish mo. ago I cut the wires that operate the self opening doors so they could be manual. I leave the power door switch off at all times. Related? The van starts well - strong - I wouldn't think it's the battery or related . . . thoughts?)

 

[dandrew.blay]

Wow, what a journey and thread! Similar issue but my engine stops too. 2014 Odyssey - symptoms are flickering power to all things, engine sputters, sometimes stops all together. Happened 1st approx 12 mo. ago - had alternator replaced & battery at a dealership (we were out of town). All has been good until today. Driving, all flickered, engine stopped. 4-way flashers did not even work. A min or 2 later, power returned, my 4-way flashers started to blink. Stared van as normal, drove home.

Do i need an OEM alternator? Will look thru and look at earlier suggestions too. Wondering about battery post spacers . . . Maybe bad connection. Other ideas?

(5ish mo. ago I cut the wires that operate the self opening doors so they could be manual. I leave the power door switch off at all times. Related? The van starts well - strong - I wouldn't think it's the battery or related . . . thoughts?)

Missing detail: 12 months ago, van was dead, no power, no way to start.