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Need HELP! Try to start and electrical system goes dead. Turn on head lights and the.

04-25-2008, 12:29 PM
1996 175k miles P71
We have owned it for 5+ years and put over 50k miles on it.

Behavior: Car will not crank/start. I was coming out of a store on Monday evening and climbed in. Turned key and nothing…. I mean nothing, no cranking, no lights (interior) nothing.


Pulled key out. Popped hood. Had a bright under hood light, had a bright interior light. Checked battery cables at the battery they were tight. Wiggled them. Stepped back into car and turned key – car goes dead. Dash board lights for ABS, Oil pressure warning, battery etc – glowed faintly and then faded in and out some after the key was turned.


I was broken down in front of a Harbor Fright store and an AutoZone. Praise GOD for that. So one cheap socket set and one voltmeter later I was trouble shooting.

Battery had 12.46 – 12.60 volts. Voltmeter read same if I had positive lead on battery and grounded on the alternator or any other ground. I tested as well from the battery cable and from the power distribution box. Etc… Wife brought out another car. Jump starting did not help. Let it ‘charge’ on the jumper cables for about 15 minutes. Car barely cranked over and started! Bam!

Pulled out of spot and went about 15 feet. Turned on headlights and car died. I mean dead. Coasted to a stop. Nothing when I tried the key. Hmm….

Called wrecker and got it home. Monday was a long day.

Here is the behavior:
- When you approach the car the interior light, under hood light door locks, remote entry every thing has full power and operates.
- The moment you put key in ignition and try your first crank it kills the entire electrical system
- You get a clicking through the EEC, A/C cut out and fuel pump relay box. You get a clicking or tow in the power distribution box and a click down at the starter.
- Battery charger showed battery at about 80% when I first put it on and then charged it up o 100%
- After you try the starting the electrical system acts very strange. The dash lights fade in and out. The interior dome fades in and then after about 10 second post starting attempt it acts normal with full power at all accessories. You can have key in on position and run the heater fan etc…
- Turn on headlights and it kills the car
- Turn headlight switch on to parking or headlight setting and it will cause the LCM under dash to make a rhythmic ticking sound while making the radio display flash on and off in time with the LCM.
- If car is running it runs fine but the moment you turn on headlights or attempt to adjust the radio it kills the car.

What I have done to the car:
- About 6 months ago we had a crank (turn over) but no start problem that we discussed here. Some times it would not even crank.
- Replaced the PCM
- Replaced every fuse, maxi fuse and under hood relay
- Replaced the battery cable kit
- Added two extra ground straps from block to frame
- Cleaned up the wiring harness of any snipped or stubbed wires from the police department

Car ran great for last 6 months seeing use of about once or twice a week.

Repaired the AC two weeks ago replacing the compressor/dryer and full flush etc….

I installed a power bench seat from my 91 crown vic. I used the existing harness from the 91 crown vic and spliced it into the harness for the 96. The only difference was the 96 had a different plug on the end - so I used the plug form the 91 and spliced it into the 96 harness installed seat.

I installed a trailer wire harness into the trunk tail light access with a separate ground. Worked great.

The AC repair, the power seat and the harness for the trailer lights had been on the car for three days of daily use with no symptoms. I have unplugged the seat harness while trouble shooting and it appears to make no difference.

So - if you go to the car right now. It would appear to have no problems. Interior light comes on when you open door. Ignition chimes when you first insert key. Turn key and BLAM – car goes dead. A click from under hood and under the dash. No dash lights then they will slowly begin to fade back in. You turn on the head light switch and the lights do not come on, however, the LCM under dash clicks while the radio illuminate with the rhythm of the clicking.

I have jumped the car off by placing a jumper cable to the starter solenoid and it will fire off and run. If you have it running it will die as soon as you turn on the head lights and then it will not restart. The radio also now has a whine in it while the car is running.

I am at wits end and need help/ please.



04-25-2008, 12:34 PM
here is a pic of the P71 with a former game warden boat in tow

04-25-2008, 02:59 PM
Have you had the ampereage of the battery checked? Voltage can be good and not enough amperage in the battery to start car. Little lights take about 2 amps. Starter takes about 200 amps.

04-25-2008, 03:45 PM
Bear with me as I probably know enough about mechanics and electronics to be dangerous...
If the battery seemed to take the battery charger OK, and if jump starting did not immediately get the car going - I assumed that it was not the battery. It by the way is probably about 3 years old and was rated as a 4-5 year battery etc...

So if the amps are too low then would that cause a drain when trying to start the car that makes everything go dead including the very strange behavior with the LCM clikcing under the dash board on and off if the headlamps are turned on?

Is there any way to test the amps with a basic voltmeter - or should I just swap in a battery that I know is good? (I can pull one from the boat that is new)




04-25-2008, 06:45 PM
I would mswap with a known good battery and see what happens. You cqan not test the amperage with a voltmeter. The amp scale only goes up to 10 amps on multimeters. You could take it to a parts hyouse and ask them to do an amperage load test on the battery. My guess is when there is about 200 amps placed on it, the volts will bottom out.

04-26-2008, 10:19 AM
Great news!
I pulled a good battery from another vehcile and it cranked right up with none of the strange behaviors mentioned above. Ran great and took all the loads of fan on high, bright lights etc...

Put old battery back in and same no start and same LCM clicking and relay under hood clicking symptoms.

Good battery back in and no problems - put old in one more time and same results. Put good one back in and moved car to shade tree for later today.

the whine in the AM radio is now very faint and I am wondering if it means the alternator is on its way out?

With the car running @ idle it jumped up about 2 volts. I did not have a chance to idle it up and run with accessories to see if it is overhcraging or not. The alternator under the hood itself makes no noise and I have a new belt and tensioner on.

Do voltage regulators go out on these cars?

I'm going to be using as a daily driver and am wondering if I should replace the alternator and voltage regulator along with the battery today. I really don;t want to if I do not have to since the alternator and voltage regulator would be about $200 for both.....

I appreciate your help. I never would have thought something as simple as the battery since it had volts and all the other weird symptoms. You have educated me - THANK YOU!



Johnny Mullet
04-26-2008, 08:53 PM
Dude! Just get a new battery made for the car and then enjoy! A weak or shrted battery does strange things on Ford/Lincoln pruducts.

04-26-2008, 10:59 PM
Took the core in and got a nice battery. I'm thinking I put the old one in when we got the car 5 yrs ago - new battery is sweet!

I found an outline for a voltmeter test you can run to determine if alt. is charging and if regulator is operating ok. Ran tet as described with the new battery and all readings are in the right range.

I never would have thought that a bad battery would cause all those strange symptoms. I now know.

Thanks for the help. I haven't posted here since the last problem and you guys jumped right in.



06-22-2008, 07:44 PM
Johnny how did you bend your wrench?

04-13-2014, 07:57 AM
Thanks for following up your original post with the solution to your problem. Most posters never close their post with what they learned - it's very frustrating!

I had this same problem on my 97 Grand Marquis and posted it in the MGM forum but received no replies. Searching through that forum I found a thread on a similar problem back in 2004 but the OP never posted the final outcome. Sent him a private message but never received a reply back.

By the time I came across your posting (searching for "ignition switch wiring" in the Crown Vic forum because there's more activity here), I had pulled out all the wiring around the steering column and under the dash on the driver's side. I was convinced I had a short in the wiring harness feeding the ignition switch because the switch tested fine but the starter wire had ~6V on it at all times and when I jumpered power to the wire going to the LCM the incoming power to the ignition switch connector dropped to 5-7V. I had planned to start disconnecting connectors in that circuit until the problem disappeared (which is why I was searching for the wiring diagram) when I ran across your thread.

New battery = problem gone! THANKS!!!

As Johnny Mullet said, "A weak or shrted battery does strange things on Ford/Lincoln pruducts."

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