Automotive electrical question

I assume this is an easy one to answer but I must not be using the correct search terms in google. Hopefully the fix will be easy!

Every now and then my car, which works perfectly fine, will just not have any electricity flowing to anything. The lights don’t turn on, the alarm doesn’t work, turning the key in the ignition causes nothing to happen. I should mention this does not happen while driving…this only happens when the car is off. Each time, after a few minutes, everything is working normally again. This has happened on more than one occasion and I thought that there must be a wire loose somewhere. I feel qualified to say this because I’ve looked under a hood on at least one occasion AND I know where the gas tank is located. :slight_smile:

This morning it happened again. The keyless entry worked fine but when I tried to start the car nothing happened. Lights would not turn on, radio not working…basically what you would expect if the battery were not connected. I got out of the car and closed the door. The force of the door closing was enough to, in my estimation, “reconnect” those wires. I checked the battery and the connections are tight. Unfortunately, this one action effectively exhausted my automotive expertise. Has anyone experienced this before? Any ideas what it could be and how much I’m looking at for a repair? Thanks in advance.

Based on what you’ve written - and without knowing the year/make of the car - it’s probably not the battery (if the remote entry works when the car is dead - enough juice to unlock would probably also turn the dash lights on) but might be the hot lead to the distribution point (fuse block) for the power to the systems that are controlled by the ignition switch…or the ignition switch itself. Both the fuse block and the ignition switch are close enough so a slammed door might jiggle them. A good mechanic with a tester can find this for you in 15 minutes.

Thanks for the reply. I was not perfectly clear about the remote entry. Everything was working fine when I used the remote entry and, then, when I went to start the car nothing, including the remote entry, works.

I’d check for lose battery terminal clamps, bad battery-to-frame connection and bad ignition relay.

Yup. If the small draw of the remote locks killed the system entirely, then cables, connections, or maybe even a bad battery. A loose plate inside the battery will kill it intermittently. Cables first. Loosen the connections and wiggle/twist them around and retighten. If nothing, go to the other end of each fat battery cable and repeat. If nothing, get it to a shop before it leaves you in the middle of an intersection.

I know it is not the battery because this has happened with two different batteries. I recently had the battery replaced and this still happens on occasion. That would seem to eliminate the battery or the connection of the cables to the battery. I’ll try the other end of the cables but the problem is that, unless it happens again soon, I’ll never really know if what I did had any effect.

I am going to the shop before this leaves me stranded. I just simply forget until it happens…and then I quickly forget again. I bet getting my car towed would remind me to take it to the shop! :slight_smile:

Year make and model would be a hell of a help here.
Is it a conventional key or a proximity key?

You checked the battery cables, but the other end can have a bad connection as well. It may not be loose enough to wiggle, yet it could be corroded enough to block current flow. These can be hard to check. The negative cable probably has the mounting end on the block or something reachable. Unfortunately, the positive cable is more likely to corrode and is harder to trace. Wiggle the cable as low as you can when this problem presents. If it starts, you know what to do (Get it to a mechanic and inform him of your discovery.)

2006 Mazda Tribute with a conventional key. Sorry I didn’t provide the info…I just assumed this is a more general problem that is not model specific.

Yes. A bad ground (as opposed to a bad battery) sounds like the most likely cause. A surprisingly small amount of jostling can result in this type of intermittent behavior. And if that is indeed the cause, whether the result of a loose connection, corrosion, all of the above, you can expect the problem to become worse over time.

Probably not a loose cable or corroded end. The car would probably not crank of the cable connection were this bad.
I would go with either a bad ignition switch or more likely a bad relay/ connection to one of the relays that power everything up when you turn the key.
I would look at the relays first if I were diagnosing the car.

I know of a case where this was caused by bad connections in the transmission interlock switch. That’s the wiring that prevents your car from starting unless the transmission is in Park or Neutral. And slamming the door might be enough to knock it back into a working condition. So you might check that.

But in the case I know of, other electrical stuff would work. For example, the dome light came on when you opened the door.