Electrical - Fuses

[Shelly Harris]

While you're under the hood, pull the fuse for the interior lights and the clock (same fuse) and your battery will never go dead.

This reminded me of a question I had. My electric windows operate when the ignition key is off. Is that normal? During the week my car was in transport the battery arrived dead. Thinking there is a leak somewhere, I then bought a battery switch and usually pop the hood to turn it off when I know the car will sit for awhile.

[Nick DeSpirito]

Yes Shelly, that is normal. Very typical for cars of the 50's. Install a cutoff switch on the negative terminal side of the battery. I have one on mine and always disconnect it when I put it in the garage. A sloppy window switch could cause a drain on the battery and maybe a fire. Better to be safe.

[Barry Wolk]

I hate battery-mounted disconnects. They are prone to melt-down due to the small surface area of the contacts.

I had to be pushed across the awards stage at the Orphan Car Show a few years ago because of a failed switch.

I never disconnect my battery. It's so simple to troubleshoot battery draw problems that they should be fixed rather than masked with a disconnect.

[Nick DeSpirito]

You're right about fixing and finding power drains or for that matter, anything else on the car that needs attention. I just feel safer disconnecting the battery.

[Barry Wolk]

Do you disconnect the battery on your daily driver? Newer cars are much more complicated, having literally miles of wiring in some vehicles. Do you have disconnects on those?

Frankly, I don't see the need on a well-sorted car. The disconnects are the cause of more fires than wiring is.

Just my $.02

[Shelly Harris]

I think Barry has a good point. However, like Nick I have a cutoff switch on the negative side of the battery and routinely keep it off in the garage. I'm going t keep using it untill I am 100% confident that I have no flakey switches, etc leaking down power. Right now the window switches and /or their solenoids seem to be acting a bit flakey, which is why I posed the question as to whether they have power access when the ignition key is off.

[Barry Wolk]

The window do work with the key off. As does the horn and electric seat.

It's incredibly simple to detect draw. You simply need a 12-volt test light. Connect the alligator clip to one side of a fuse-holder (after removing the fuse) and touch the other side with the test probe.

Do this in a darkened garage. A draw will present itself in the glowing filament. Once a draw is determined it's easy to find the source.

[Mad Scientist]

If a car is going to set unused for an extended period of time it makes sense to disconnect the battery. Something as simple as a light in the glove box that didn't turn off will run the battery down.

Unfortunately when a modern car battery is completely discharged frequently they will not take and hold a charge the why they once did.

[Barry Wolk]

If a car is going to set unused for an extended period of time it makes sense to disconnect the battery.

I would agree with that. What do you consider an extended period of time?

[Nick DeSpirito]

I haven't had mine out since the middle of May, so it's been around 2 months.

[Barry Wolk]

I drive mine every chance I get during good weather.

[Mad Scientist]

I would agree with that. What do you consider an extended period of time?

If the car is going to be hibernating during the winter then I would disconnect the battery. Also once or twice during the winter connecting it to a battery charger is not a bad idea. A battery will discharge even when not connected to anything due to its internal resistance.

[Barry Wolk]

Resistance is futile.

[CarMan]

A quick disconnect battery switch can also make it harder for your car to get stolen. Let's say you store it somewhere, it offers a little extra peace of mind.

I don't have a mark 2, but I have these disconnect switches on both my GTOs. It's also a nice way safely replace light bulbs. I like to disconnect the battery, then do the bulb replacements.

[Barry Wolk]

The hood release on the Mark II is on the outside. No switch on the battery would stop anyone from stealing a Mark II.

[Mad Scientist]

To prevent your MKII from being stolen you need to go back to a tried and true method.

Get a Dalmatian!
http://i68.photobucket.com/albums/i17/mscientist/MKII%20rebuild/watchdog.jpg

Prior to chasing the horses on old horse drawn fire engines as a means of making them run faster they were used as guard dogs when a gentleman rode his carriage into town. The dogs considered the carriage their property and stayed by it and keep strangers away.

However in this case so long as a stranger was willing to take her for a ride she would be OK with that. :)

[Ian Cowie]

My windows and seat controls have quit .... worked last time I had the car out but this past weekend when I took it out to a show they just refused to work.
I had worked on a couple of electrical problems such as replaced the fuses for the interior lights and the under hood lights. I noticed that some previous owner had rerouted the hood light wiring directly to the red wire on the start solenoid. So I removed the wire and rerouted it to the fuse box. There was already a wire on the hood fuse but I could not trace it (disappeared into a big bundle and I do not have ANY documentation or manuals other that what you kind people can offer.) I pulled off the existing wire and taped it up and installed the newly rerouted hood light wiring to the fuse.
I do hear a relay seeming to click every 2 or 3 seconds and if I leave the car for a few days, the battery goes dead. So, I have been removing the negative cable and it definitely sparks (no dark shed needed to see the draw Barry!) when reconnected.
So, fuse(s) for windows and seats?
Schematic?

Thanks every so much folks!
Ian

[Mad Scientist]

You obviously have a major current draw on the battery.

Try disconnecting the battery then place a small light bulb, like the one in the glove box, between the battery and the disconnected cable. It will undoubtedly light.

Then start removing fuses one at a time until it goes out. That fuse will determine the offending circuit. Then we can get you a copy of the schematic for it.

[Barry Wolk]

Mad gives good advice. A draw that big will be visible flashing the individual fuses to their holder.

Sounds to me like the switch has a welded set of contacts that is sending constant power to the seat motor, causing the large draw.

I have a great schematic for the whole car. I'm hoping it's public domain. I'll try and post it tomorrow.

[Barry Wolk]

Can't get my scanner to work after a recent update.

Did you determine which circuit?

[Ian Cowie]

Well, I removed ALL the fuses and reconnected the battery and I still heard a relay clicking.
Disconnected the battery ground and put a test light from battery ground to the ground cable and it lights up.

So, I started removing wires and found a black wire with a white dot connected to one of the 3 square devices mounted right behind the fuses. I then had a hunch it was related to the electic windows/seats so I pulled the switches out of the door panel and found each set of switches had a black wire with a white dot. Pulled the two wires, reconnected the battery and viola! No relay clicking. The test light between battery ground and ground cable did NOT light now.

I then had a hunch that the 3 devices mounted behind the fuse rack were circuit breakers and that one of the breakers kept tripping and resetting. Reviewing Barry's newly posted diagrams confirmed my assumption. I then then reconnected the wires and miraculously the windows and seat now work! Some of the driver mounted window switches are marginal or simply don't work but using the other switches I confirmed the windows are all working. Well, the right rear needs some manually pulling to help it go up!
Now to track down some other wires that have been added and rerouted!!
Thanks again Barry!
Ian

[Barry Wolk]

The Mark II windows are controlled by relays that are in turn controlled by the window switches. I've had mine apart. They were corroded and the grease has turned to mud. A simple cleaning of the contacts is all you should need to do to restore the switches.

The relays can be pried open and serviced, too. Get a contact file. That will allow you to file the contacts parallel to each other, providing greater mechanical surface area contact.

Be aware that the switch handles are directional. I put two of mine in backwards and they stick out like a sore thumb, to me.

The control wiring for the windows is simply in parallel from the master switch to the relays and remote switches.

Check that your barrel bullet receivers on the switches are nice and tight, loose connections play havoc with these cars.

Take lots of digital pictures before and during disassembly.

[Mad Scientist]

As Barry mention the nice thing about these switches is that they are servicable. I had a couple on the drivers side that only worked in one direction.
But be sure to work in a clean well lit area where you can lay out the pieces in the order that you remove them and will not have a chance of losing any of them. Also use care when removing spring clips.

[Ian Cowie]

So, I removed all the window switches and disassembled and cleaned.
There was a chunk of steel wool inside one of the switches and I think that is what shorted and caused the continual drain on the battery. In addition that switch had one of the two contacts completely burned out. Just a small hole in the brass where the contact was originally riveted in. Any body have a spare switch or know where I can get one? Also need a couple of the metal spring clips (the small ones) as there are missing.
Barry, you mentioned grease. I can't say I noticed any. Should I have used grease when I reassembled the switches?
Ian

[Barry Wolk]

Grease is not necessary, but helps on the pivot points of the rocker switches. Use "dialetric" grease, as it doesn't conduct electricity.

How did steel wool get into the switch????????????:eek:

[Mad Scientist]

In addition that switch had one of the two contacts completely burned out. Just a small hole in the brass where the contact was originally riveted in. Any body have a spare switch or know where I can get one?

If you cannot find a replacement switch you might consider buying a similar type switch and take it apart to see if you could remove one of its contacts and graft it into your switch.

This would be a real pain in the a$$ but it might work as a last option.


I guess this is another reason why not to use steel wool to clean chrome. :rolleyes: