it sounds like a parasitic draw somewhere - a door left ajar, a light left on.. or some circuit somewhere; especially if it drained out without you driving it, unless it's sat for months and months. how long has it been since you last drove it? while the car was honking , was the PATS light (red) near the defrost button blinking, or a solid red? have you considered push-starting the car to get it started, and letting the alternator charge it up from there?

 

It's my daily driver and I had driven it Wednesday 2 days before it no longer started. I don't remember if the PATS light was blinking while it honked or not. It's hard to see in the day light, but when I did look at it, it was blinking.

I don't think doing a push-start would work because it doesn't even try to turn over. The radio doesn't work, the power locks aren't working, and I can't tell if the headlights are working (the fog lights do).

So, I hooked up my OBD tester and it said it didn't get a connection. I had to remember how to remove my ECU and got it free from the top of the engine. I opened it and really didn't see any damage. I then tried starting it with the ECU back in, and then without the ECU plugged in and they both did the same thing. The gauge needles just go all the way full tilt and back with just the ABS, seat belt, oil, and battery lights lit on the dash. I suspect the ECU died and ordered a refurbished one.

Maybe that'll fix it. I'll do some more forum searching, but a lot of it isn't here anymore.

 

This feels like a battery cable issue.
Try jumping the starter directly.

 

I had that happen to me years ago and it was a bad alternator.

 

The v6 series alternators by ford had an initial problem with built in voltage regulators. Have the alternator tested at an alternator rebuild shop and ask them to look for parasitic draw. Also MAKE sure the mega fuse has a plastic housing on it otherwise it may be close enough to ground such as the body or engine that’s causing a small short that will drain a battery in no time. If you doubt the 175 amp mega fuse they sell them in isle 2 at autozone for 5 bucks.

 

Haven't been here in forever, email notification found me, thought I may save you some headaches. Had similar issues on 1999, no crank but everything seemed normal except couldn't connect code reader.
Trip to pull-a-part and around $10.00 new to me ignition switch and all is well. Just saying

 

The last shop I took my car to replace my the alternator I just took out told me that it was still good. I replaced it anyways. I've replaced my battery cables and the mega fuse at the same time. After all that work, it still does the same thing.

I will take a look at my ignition switch.

 

https://www.cars.com/research/mercury-cougar/recalls/

 

Recall Number
04V421000
Recall Date
08/30/2004
Component
FUEL SYSTEM, GASOLINE
Summary
ON CERTAIN PASSENGER VEHICLES, CONTAMINATION OF THE FILTER IN THE FUEL DELIVERY MODULE (FDM) CAN REDUCE, AND EVENTUALLY BLOCK, THE FLOW OF FUEL TO THE ENGINE.

Consequence
THIS MAY CAUSE ENGINE HESITATION, LOSS OF POWER, SURGING, AND OTHER SIMILAR SYMPTOMS. OVER TIME, THE FILTER MAY BECOME SUFFICIENTLY BLOCKED TO CAUSE THE ENGINE TO STALL, WHICH COULD RESULT IN A CRASH.

What Owners Should Do
THIS ACTION IS DEEMED A SAFETY IMPROVEMENT CAMPAIGN AND IS NOT BEING CONDUCTED UNDER THE SAFETY ACT. ALL OWNERS WILL BE NOTIFIED OF THE PROBLEM, AND DEALERS WILL REPLACE THE FDM WITH A NEW DESIGN AT NO CHARGE IF THE OWNER REPORTS THAT THE VEHICLE EXHIBITS ANY OF THE IDENTIFIED SYMPTOMS. THE FREE REPLACEMENT WILL BE AVAILABLE FOR A PERIOD OF 10 YEARS FOLLOWING THE ORIGINAL PURCHASE OF THE VEHICLE, WITH NO MILEAGE LIMIT. THE CAMPAIGN BEGAN ON APRIL 16, 2004. OWNERS SHOULD CONTACT FORD AT 1-800-392-3673.

 

Cool thing is you don’t have to drop the tank. It’s access hold is under the rear passenger seat.

 

No fuel system problem is ever going to result in a no-crank situation. So forget about that right now.

No crank is either an electrical problem or a bad starter.

 

So, I was trying to check for my ignition switch. I unplugged it and plugged it back in. Then I found my fuse box under the steering column and I pulled out and checked all those fuses. Nothing was blown at all. I hooked up my battery and I had normal power again. So, I put my computer back in and tried to start it and nothing.

I decided to go back to Autozone and have them check my battery. They took it and said they'd charge it because it was at 8v after I charged it before. I took my second battery and used it as a core for another battery. I put the brand new battery in and it started! I let it idle for 5 minutes to see if anything was wrong and it seemed ok. I'll pick up the other one today to have that spare again.

I don't see how I could 2 bad batteries though. I am going to do some electrical testing on my car to find any open circuits when I get some spare time. Maybe that'll fix it for good.

We'll see how it goes today.

 

I would like to re-iterate my bet : parasitic draw from a short in one of the electrical systems. You let the car sit, it slowly drains the battery all the way down. Simple as that. Some shorted circuit somewhere that constantly draws. No broken parts, no computer issues, just a wiring fault.

Also, if you pulled a box from the top of the engine, particularly if it's the V6, the box out front-top is actually the IMRC (intake manifold runner control) box. It*s only a motor and board that open up secondaries in the intakr, beyond 4000 RPM. It handles no other function.The ECUs on these cars is actually behind the glove box, above the passenger's feet.

Lastly, I'm human and make mistakes like anyone else, so i could be wrong, but nothing you describe tells me it's ECU related, and a battery going flat while sitting isn't going to be an alternator issue, either ; if the battery light doesn't come on in the dash while the var is running, then the alternator (and indeed the whole charging system) is fine. Indeed if the car starts up at all (which it does with a charged up battery) , then the ECU is also fine.

I would start pulling fuses to the radio, interior lights, fog lights, etc, by process of elimination, or i'd start measuring resistance values for every circuit. Something's off with those. I'm confident it is so.

Best of luck to you, i hope it hasnt been too much of a downer so far.

Sent from my SM-A530W using Tapatalk

 

...Lastly, I'm not an automotive god, i could be wrong...

Wait...what?

 

When you want to sell that car, lemme know.