1973 Custom Cruiser

I was thinking more about that thing that looks like a relay, and I'm wondering if it isn't part of the tailgate motor circuit. I looked in the owner's manual, and a feature on these Custom Cruisers prevented the tailgate motor from working if the car was not in park or neutral. Could that relay in this photo be the thing that senses whether or not the car is in park? Maybe that's been my problem all along. Maybe that relay has failed and is preventing power from getting to the dash or rear-of-car switch because it failed in the car-is-not-in-park mode. The connector to that relay has three wires. One is another orange/black which is probably power (I could pull it off and check.) The red/white wire perhaps is from whatever senses whether or not the car is in park or neutral, like the neutral safety switch. The purple wire might just be a return? Gee, I wonder if I just pulled that connector off and hooked the orange/black wire directly to the purple one what would happen. Explosion? Fire? Before doing that, I'll pull off that connector and see if 12 V is present on the orange/black when the ignition is on and if 12 V is present on the red/white when the car is in park or neutral but not if it's in gear.

If that relay, whether this is it or not, has failed, I could just bypass it. That would cause the tailgate to work all the time, not just when the car is in park. But I could trust myself not to open the tailgate when the car is moving!

 

keep in mind that the rear key does not need the ignition to be on, if you have no movement with the key, then you have other troubles. I have just gone through 2 switches, and it may be that the switches got burned out by a not tight neg battery cable.

when I hit the window switch the other day, the car died. My mechanic said they are not related, but when I hit the window switch the other day, the car died.

seems related to me

 

Jaunty, that relay is a small transformer type, that acts like a voltage reducer and bumps up the amperage to the device that it serves. Most of them are, anyway. They either reduce the incoming 12 volts, like the power to the dash gauges in my car, from 12 volts to 5.1 volts, or they amplify the amperage. On the latest cars, they actually call them voltage amplifiiers. They do break down, but there's only a handful of manufacturers that make them. That means that you could find a replacement from Autolite or MotorCraft or even Delco. Your manual's text should describe the input/output ranges (Volts and Amperes) and then you could find a vendor with an equivalent unit.

The grounds need some attention, if your wiring is getting fried like that. Pull them off at the frame or body tin and clean them up, at least. I replaced all of mine with #2 AWG (Big cables) and my Halogens shine like the noon-day sun, without any relays!

There's two ways to renew the body/frame contact points, but you have to clean the area down to bare metal. One is to spray a galvanized coating on them, the other is to heat up the tin and apply solder to it (tinning the metal). Motors, body grounds, starter, major dash grounds to relays, the voltage regulator, headlights, etc. etc.

Check this out:
http://www.the12volt.com/installbay/forum_posts.asp~TID~73496~PN~1

 

I realize this. I'm wondering, though, if the rear key switch is also controlled by the same relay that prevents the front switch from working if the car is not in park or neutral. After all, you would not likely be trying to open the gate from the rear key while the car is moving, so you would never have occasion to notice that that switch is also controlled by the relay.

To be honest, I would be willing to forgo use of the rear key switch for the tailgate if I could just get the dash switch to work and the motor to move at all. I'm thinking that if I can't locate the relay that controls the dash switch that I might just run a wire directly from the accessory block to the dash switch. I'm a big boy and can remember not to try to open the tailgate while the car is moving.

There's apparently another relay in the system somewhere. The owner's manual also says that there is a safety feature built in that prevents the tailgate from being operated from the rear key switch unless the window is open at least 8 inches. That means there has to be a position sensor on the window somewhere to tell the key switch that it's open that far. If THAT sensor or relay is not working, then perhaps IT'S preventing the rear switch from working and maybe even causing the problem with the system overall.

As I said earlier, unfortunately, there is no wiring diagram in the service manual that covers station wagon-specific electrics, such as the tailgate and window motors and their wiring.

I agree with you. You must have caused a momentary grounding of the system somehow that killed the engine.

I hate electrical problems!

 

Thanks. It would be nice to know what that relay/transformer controls. Wiring diagrams are great to trace wiring because they give you wire colors, switch pinouts, and so forth. One thing they don't tell you is WHERE in the car the various connectors, relays, transformers, switches, etc. are located. Something like that would be REALLY helpful do the do-it-yourselfer.

 

Jaunty does anything work? I mean window or tailgate from switch or key? The tailgate area is covered in the Fisher Body Manual, I have one if you need access to it, KIM that the oldest I have is 75 but I think the clamshell was the same but you never know. Anyway would be happy to scan if you need.

 

The rear window works fine from both the dash switch and key switch and always has. But it's on a different circuit than the tailgate motor. As I mentioned earlier, the tailgate motor is on the same "accessory" circuit as other power features, including the power seats, power windows, and power locks. All of these are high current-draw, momentary use items. It is a bit puzzling that the power windows in the doors would be on this circuit but not the rear window, but that's the way it is. These are protected by a 40-amp circuit breaker.

My car does not have power windows or locks, but it does have power seats, and they work. This tells me that power IS getting through the circuit breaker to the accessory block. So my problem must be in the connection from the accessory block to the dash or rear key switches. There's only two wires coming off of the accessory block, and I know which one is for the power seats because I traced it, which was easy to do with the carpeting and seats out of the car.

That means the other wire coming off the accessory block must be for the tailgate. But that wire disappears into the wiring harness to emerge I know not where. I presume it attaches to whatever relay prevents the tailgate motor from operating if the car is in gear, but I have no idea where that relay is or what it looks like, and the manual is of no help. If I were designing the car, I might connect this to the neutral safety switch, so maybe I should look there and start trying to trace wires. I mean, there is already one device which senses what gear the car is in. Why put in two?

So, like I said, I may just bypass the car's internal wiring and run a wire directly from the accessory block up behind the dash to the dash switch. The circuit would still be protected by the circuit breaker. I just wouldn't have the relay preventing opening while in gear in the circuit, but I can live with that.


I do have the 1973 Fisher Body manual, by the way, but, to be honest, I have not looked at it as closely as the chassis manual as it's the latter that has the electrical system in it. But I will take a closer look at the body manual.

I can sometimes find no rhyme or reason as to what's in the body manual versus what's in the service manual. For example, the hood, by anyone's definition I would think, is part of the body. But instructions for adjusting it are in the service manual, not in the body manual.

 

ok good information - with that said, can you jump power at the motor to see if it works? maybe right from the battery? I know my mechanic did it with my convertible top last month, also on the same circuit you described above, but in 75 I think the window is on the same circuit as well, at least the same 40 amp breaker as seats, etc. sorry if I missed the thread where you tried this and reported it. My mind is going very quickly these days

 

No problem on the going mind. Mine is right behind yours!

Yes, early on, I removed the motor from the car (this allowed me to manually raise the tailgate to the full up position--it had been stuck down about four inches) and hooked it directly to a 12 volt power supply, and it worked fine. I've tested the wires connecting to the motor, and there is no voltage present on either of them when the key is on and the dash switch is pushed either to open or close. So the issue is a lack of power getting to the motor.

 

Us Ford guys are spoiled. They make an EVTM for us. Electrical Vacuum Trouble Shooter Manual, with excellent colored sketches. Kind of like Wire-By-Numbers. Even us old farts can figure it out!

 

right I remember now, it came home open and you wanted to close it to clean it and you did. I remember. So it's easy - just a little puzzle to fix some wiring, here is a hint - it will be in the last place you look, so look there 1st! Sorry, couldn't resist. FWIW when I was having drama with my window (up to and including this past weekend) I heard the relay "clicking" from the way back R/R sounded like under the key switch / spare area. I bet David's threads show it, and that's a 72, but I feel confident that all years clamshells were pretty similarly set up

 

I would not have thought to look in the rear of the car for the relay as it would mean running an extra wire all the way from the neutral safety switch or whatever senses the gear position to the rear of the car.

I don't hear anything when the key switch or the dash switch are moved. I have no idea about this relay and how it might have survived the last 37 years. I DO know from my various investigations that there was apparently a fire and/or water exposure under the left side of the dash, most likely due to an accident, that resulted in some of the weird wiring I've talked about earlier.

One thing I found when I removed the seats and carpeting and was vacuuming up 37 years' worth of sticks, stones, and dirt, was a few pieces of broken glass. I'm sure that this accident I've been talking about resulted in at least one shattered window, and I know how hard it can be to get every last piece of glass out of a car unless you completely remove the interior.

If the left side radio speaker can look like it went through hell (I showed a photo of it earlier in this thread), there's no reason this relay I'm looking for couldn't be in a similar condition if it's located in the same area under the dash.



From the records I have, this car went to the body shop in October 2004 and stayed there until March 2005. It was completely repainted to the tune of whatever $5,000 buys you, and the invoice also mentions "collision damage repair." My guess is that the body shop did lots of electrical work, too (or farmed it out), in bringing the car back to life, and when it was returned to the owner, a few things still didn't work. These included the left side radio speaker, the tailgate, and the taillights/dash lights/parking lights. My guess is that he was in the process of investigating these problems when his health started to fail and he ultimately stopped working on it and never returned. It explains why the rear interior of the car was partly disassembled, although if it were me trying to find the problem with the tailgate motor, I would have started more toward the front of the car after, of course, confirming that the tailgate motor itself was still working.

If, for example, you want to check the wiring from the motor to the front of the car, there's no need to rip up the car to get at the wiring. You can just test for a complete circuit with an ohmmeter. If I get continuity from front to back on each of the purple and green wires, I know that there is no break in the wire between the motor and where the wire connects to the front wiring harness.

 

have you seen this?

Fisher Body Clamshell Tutorial

 

Yes, this looks like it's from the Fisher Body manual. As I said, I've got to stop dissing it and take a closer look at it!

 

Puts a whole new meaning to Clambake!

Sounds like you're on the trail. Good luck.