What is this relay

[murdoc rose]

I've been doing connection test all day with the same wiring diagram that's on the site. So far only having 2 questions is impressive.

The first being the title. I have a relay mounted on the firewall that to my knowledge does not appear on the diagram. Its next to the hood latch on the passenger side. Any ideas?


The second question has to do with grounding. I thought my 58 was a positive ground car but the diagram suggest otherwise.

[jopizz]

The relay is most likely the power window relay. Does it look like this. There's a separate diagram for power windows. Squarebirds are negative ground.

John

[simplyconnected]

John is on the ball tonight with an excellent picture and he's correct on all counts. The general schematics don't cover accessories like power windows, power seats, convertible top, sequential signals, etc. (if your car has any of these).

1955 was the last year for six volt systems on Ford cars. I have one.

The large box mounted to the firewall is the relay and the small box is a circuit breaker. CAUTION: Yellow wires are UNfused battery power (+12) coming from the starter relay. At the mentioned circuit breaker, overcurrent protected power feeds the relay contacts. The relay coil is energized from the key switch. Sometimes this relay is used to feed the convertible top motor as well.

Important to note; the relay box needs a good ground, much the same as your starter relay, or it won't energize. So, make sure they are tightly bolted down with no rust inhibiting 12 volts.

If you have more questions, please ask. - Dave

[murdoc rose]

Thanks for the fast reply. That is the relay for sure. The negative grounding has me concerned though.

[simplyconnected]

...The negative grounding has me concerned though.

Why? All domestic cars have neg gnd for decades, all the way up to the present. What are your concerns?

[murdoc rose]

My Bendix will kick in and turn the motor while on positive ground but not on negative ground.

[simplyconnected]

If you are talking about your Squarebird, the Bendix gear is not electrical. These starters are called 'inertia' starters. They do not have solenoids that force the Bendix gear, either. Here's a site I made showing the entire starter... CLICK HERE

Regardless of polarity (how you hook up the battery), your starter motor will always rotate the same direction. (Don't believe it? Try it.) Why? Because in order to reverse a DC motor's direction, either the polarity of the field wires or the armature wires must be reversed. Since they are connected internally in a series, reversing the battery polarity reverses BOTH the field & armature wires. Reversing both effectively means there is no change in magnetism direction, which dictates rotation direction.

Whoever told you that pos or neg ground is better one way or the other doesn't understand the electrical operation.

A DC motor with permanent magnets will reverse direction because again, you are only changing the armature polarity, not the field. Only modern cars have permanent magnets in their starter motors.

Some folks have ran their classic cars for years, not realizing that the battery was connected in reverse. All Squarebird motors have no permanent magnets, not even the heater motor. The clock uses a solenoid 'clapper' to wind the mainspring, gauges use bi-metal (heat) strips to move the needles, and the generator is the same story as the starter motor.

So, do not fret over negative ground. 100% of modern cars use it. - Dave

[Tbird1044]

Very nice series of pictures on how to rebuild a starter. Here is something that I ran into. I rebuilt the starter and had problems within a pretty short period of time. After pulling the starter back out, I found that both of the armature bushings were completely worn out. I knew I had replaced them, so the only thing I could think of was that the drive was not disengaging from the ring gear. I tested the starter drive by putting it on a piece of 1/2" s.s. tubing and then pressing the drive gear against a wire wheel or buffer wheel attached on my grinder. You could also use the armature shaft after the drive pin is removed. When you spin the starter drive in the correct rotation, the drive gear should retract and stay in the retracted position. I couldn't get it to do this. I bought a new drive and did the same test and it worked fine. I replaced the starter drive and bushings and things have been good so far. For reference, my original starter drive looked good, would slide freely on the acme thread, but didn't appear to retract like it was supposed to. I think the engine needs to get to about 300-400 RPM for the drive to retract. Testing my memory on this number.

[murdoc rose]

Thanks for the great link, bookmarked for sure.

[toddgilroy]

Resurrecting an old thread due to some questions re: connections to the window relay. I have a 60 convertible with power windows and driver seat. After getting a new dash wiring harness in, finished the rest of the connections per wiring diagrams and the Electrical Assembly Manual.

I now have brake lights and power to the conv top, (little victories ), and have power to the seat and windows, but just get clicks in the window relay and the top switch control relay when I try to start the car. I do have the conv top connected to the neutral safety switch with a jumper to the neutral safety switch wire, so I don't think that is the issue.

First picture is my new wiring...One thing that seems odd is I had to use a little jumper from the 30A circuit breaker on the front of the window relay over to the right side to get power to the windows...is that a sign the relay is bad (or bad connection)?

Second picture is prior owner setup. Prior to rewiring, the car started, had power to the seats and windows, but not the top. Also, the prior owner did not have either circuit breaker installed, just appeared to bypass the relay.

Thanks!

[jopizz]

The thin red wire on the left side of the relay is power from the ignition switch. You should have 12V there with the ignition switch either in the ON position or the ACC position. The front post is powered by the starter solenoid and should have 12V all the time and the post on the right is the output to the window switches. The way you have it jumpered it could be a bad relay or you are not getting 12V from the ignition switch. Put a test light or voltmeter on the left post and turn the key on. If you have power then the relay is bad. If no power then the ignition switch or wiring is bad.

John

[toddgilroy]

Thanks John. I removed the relay, cleaned all the contact points, reinstalled it (without the jumper) and checked for power per your instructions and everything seemed fine.

Then went through the starting system troubleshooting steps in the shop manual which pointed to the ignition switch being the problem. Ran to the auto parts store for a $10 universal switch and after a little coaxing it started.

Thank you for the help.