Turned key and no power

Hi. I have owned my 1990 348ts for 6 years. I rarely post but have read lots of helpful posts.

The strangest thing happened to me today. Drove the car last Thursday (4 days ago). Today, I put the key in ignition and turned it to different positions, but absolutely nothing. No lights on the dashboard.

I proceeded to try to troubleshoot. But it has been a fruitless search. I even got a new battery, etc. But nothing. And prior to buying a new battery, I used 2 different jumpstart packs but nothing.

As a disclaimer, I am an electrical engineer, so this should not be difficult. But I'm completely stumped.

You know how if you disconnect the battery, then reconnect, all the door locks would engage. Well, not even that is happening. And hazard lights IIRC should flash regardless of whether the ignition is on. Not that either.

I've cleaned the parts that mate to the terminals of the new battery. Checked the continuity of the bullet connections before and after the bullet. Everything seems to be good. Again, now I have a brand new battery in there which has also been charged via trickle charger.

And I looked for a kill switch somewhere but didn't see any. I even peeled back the passenger footwell area and didn't see any kill switch either.

I even took apart the steering column cover to get to the ignition. There is a multi-cable connector (around 8-10 wires) - one end comes from the ignition, the other end go to the firewall. I disconnected the connector, and used a multi-meter. Saw 3.5V between the red and black thick wires on the connector that leads to the firewall. Is that normal?

I don't have a wiring diagram of the ignition, but obviously power and ground goes to the ignition, and depending on the key position, a third wire would be energized. I'm not sure what voltage would go to the ignition though - was thinking it might be 5V if it's a transistor circuit.

Again, 6 years of owning the car and have never seen anything like this. Any ideas would be appreciated.

 

Yes. I cleaned and checked both. There is continuity (ie. buzzing it out).

Looks like the bullet at the battery is for -ve, while the one below the oil filter is +ve.

 

Yes, everything is dead.

I looked at your thread. Thanks! - http://www.ferrarichat.com/forum/348-355-sponsored-bradan/202861-348-starter-relay-modification.html

I think I'm one step closer. Measured the voltage between the "buss bar" to the left and the ground cluster to the right. What I got are:

- 7.3 V when ignition is off
- 3.1 V when ignition is in accessory
- 1.5 V when ignition is in "on"

Initially when ignition was off, I measured 9.6V before turning the key to the various positions. Which is a bit odd.

Are the voltages above normal?
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So the buss bar is supposed to be 12V?

I'm using a new battery already. My next step might be to cut away the majority of the existing battery cables / bullets and replace with new cables. I see resistance around 300 ohms in a short span of the existing cables.

 

The new battery is at 12.7 V. I also put it on the trickle charger and it showed it was fully charged. Aside from that, I got good sparks from it when touching the two tips of cables together (I was on the phone with an Indy specialist and he asked me to do that).

My original battery in there - a year old Optima Red Top - it was trickle charged too.

 

Finally found the culprit.

If one knows where to look, it would only take a few minutes to find AND fix the problem. But since I wasn't looking at the right place, it really led me down the garden path. I took so many things apart in order to rule them out. Eg. I took apart the steering column cover since it could have been a bad ignition switch or loose wires ...

Miltonian and the others pointed out the buss bar behind the passenger footwell relays, and that it's directed connected to the positive terminal of the battery. This got me connecting a jump pack right there at the buss bar - and sure enough I had dashlights and was even able to start the engine. This was the first time I had assurance that all the other parts of my car was fine, and the problem was getting the voltage from the back to the front.

The ground connection was fine - impedance was 0 ohm between the battery terminal and the clutch pumpkin housing.

I ended up getting rid of the +ve terminal bullet connector which like Daniel said is under the oil filter - but the problem persisted.

The problem really was with the other cable from the +ve terminal - the one running to the left in the photo. It's a secondary connection via another nut - and it's on so tight and corroded and I couldn't even undo it. But when I tested the impedance between the +ve terminal and say 2 inches to the left of it on that cable - I got about 70 ohm. That's a lot for such a short distance.

And that cable goes to the back of the car then run up the side all the way to the front. That's the +ve voltage for the dash lights and basically power for the cabin / non-engine related.

Whereas the cable from the +ve terminal going to the right toward the engine - that supplies all the engine related functions.

Hopefully this will help whoever experiences the same problem!
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Thanks everyone for your contribution! Would have taken a lot longer to track down the root cause if I wasn't pointed in the right direction.

Once again, the faulty battery cable (or connector) in this case is the one without the bullet connector so it's harder to troubleshoot as you can't easily break it apart (although you can still test impedance easily if you have a sharp test lead like I did). And the way it connects into the +ve terminal, the appearance is that it's an auxiliary cable because it is added on via a nut and it's somewhat thinner. Plus it disappears into the back of the car vs the other one which leads to the engine area.

So all in all, it's a little tricky to diagnose. But if you turn the key and NOTHING whatsoever including no dash lights, that would be where you should look =)