Wiring Questions

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Wiring Questions

Postby acstestinc » Thu Jan 18, 2007 5:52 pm

Trying to resolve some wiring issues on my 78 Spyder (V8 & A/C):

1) Under hood located between engine and A/C at firewall
- 1 orange wire has been cut (can't find other end) The only thing I find in the wiring diagram is that it may be circuit #52 (Feed, Blow SW. Hi or Max Cold) But Hi speed and Max A/C appear to be operating properly.
- 1 connector with brown wire not plugged in (can't find anywhere that it might go)
- See attched picture (the loop in the middle in the tranny dipstick)

2) Under dash
- Seat belt warning light in the dash and "warning buzzer" not working (dome light works fine, all fuses are good). I tried to check the buzzer itself but the manual is not clear as to where to apply power. This buzzer has four contacts on each side but wiring diagram shows 4 and 2. Buzzer does give a little sound as you plug it back in. I think this unit also buzzes if the key is left in the ignition.

Any ideas ?

Thanks
Paul
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Postby marco_1978_spyder » Thu Jan 18, 2007 6:58 pm

I know a brown wire goes to the tach feed on the dist.

Was there a temp sender in the head in between cyl 6 & 8 ?
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Postby acstestinc » Thu Jan 18, 2007 10:26 pm

Marco:

Tach is working fine and all three plugs are connected to the distributor. The one I'm asking about can't reach the distributor. It can only reach the A/C unit on the firewall.

I'll look into the temp gauge.

Thanks
Paul
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Postby acstestinc » Thu Jan 18, 2007 10:43 pm

Temp gauge sending unit is in the head between the last 2 spark plugs, on that side, but it is plugged in and uses a different type of connector with a dark green wire.

I'm still looking. Anymore ideas ?

Thanks
Paul
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Postby zeke » Fri Jan 19, 2007 12:07 am

Ah the GM Buzzer Box that a lot of people used to pull out and throw away! :lol:

Pin 1 - Accessory Power +12 V when key is in run position or accessory position

Pin 2 - Seat Belt Lamp (positive output)

Pin 3 - Ground

Pin 4 - Grounded when drivers seat belt is plugged in

----------------------

Pin 6 - Grounded when key is in ignition cylinder AND door is open. goes to key minder switch in column, other side of that switch goes to door pin switch.

Pin 7 - Battery + 12 V always

Pin 8 - Not used on my 79

Pin 9 - Not used on my 79

----------------------

The buzzer box internal schematic is drawn wrong by GM I believe. Pins 3 and 4 are reversed. I have corrected them in the 2nd diagram.

Function 1:

If you open the door AND leave the key in the ignition, Pin 6 is grounded, which completes the circuit thru the buzzer to battery positive.

Function 2:

When you turn the key on, power flows from Pin 1 thru the normally closed contacts of the relay out to Pin 2 which turns on the seat belt light and forward biases NPN transistor Q1 which turns on the buzzer. When you plug in the seat belt, Pin 4 is grounded thru the switch in buckle and the relay coil is energised thereby turning off the buzzer and light.

I'll have a look and see if I can figure out what your brown and orange wires r.
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Postby acstestinc » Fri Jan 19, 2007 7:50 am

Brown wire is partially solved.

It's the blower motor high speed circuit. The odd part is that the wiring diagrams shows 1 brown wire coming from the speed control resistor, going into the passenger compartment and connecting to the A/C controls. My car has a second brown wire coming from the same plug ,on the speed control resistor, and ending at the connector that I show in the picture. I've looked and just can't find anywhere else on the A/C box that it might connect to.

Thanks for the "buzzer" diagrams Zeke. I'll check it out today.

The 1 that still has me concerned is the orange wire that was obviously cut.

Thanks
Paul
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Postby acstestinc » Sat Jan 20, 2007 1:22 pm

Well now that I'm looking at the correct year wiring diagram, (I orginally was looking at 1980 instead of 1978) it appears that that mystery brown wire with connector might be for an engine temp cutout for the A/C if the engine was overheating. It appears that it might not have been installed on V8's.

The orange wire is still a mystery and a concern because it was obviously cut. But was it done at the factory or by the previous owner's husband ? I wonder if it also has to do with the engine temp cutout?

Paul
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Postby MIKESMONZA » Sat Jan 20, 2007 1:42 pm

ACSTESINC; :arrow: I TOO HAVE NO RELAY FEED WIRE BUT I EXTENDED IT FROM WHERE IT WAS CHOPPED,, DUE TO PREVIOUS OWNER :arrow: BUT MY 75 SCHEMATIC SHOW'S THIS "ORANGE WIRE" TO BE THE WIRE COMING FROM THE FAN SWITCH TO CONTROL THE SPEEDS ON THE BLOWER FROM THE RELAY AND WHEN I GET THE "RELAY" AND HOOK IT UP. :arrow: I SHOULD HAVE HEAT AND POSSIBALY A/C WHEN GET THE A/C PART'S INSTALLED BUT FOR SOME REASON I HAVE NO FUNCTIONING GAUGE"S AFTER THE INSTALL OF THE MOTOR.,,,, :roll: :roll: MIKE
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Orange Wire

Postby vermontspyder » Sat Jan 20, 2007 1:55 pm

Paul On my wiring diagram I have a Orange wire going from the Blower Control Switch to what the diagram has as a HI BLO RLY. It must be a relay. This relay has wires comming from the blower motor. The compressor has one dark green wire and black ground wire. This is a 79 Diagram. If you need any more info let me know.
Mark
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Postby acstestinc » Wed Jan 24, 2007 6:58 pm

Well I solved my underhood wiring mysteries.

- The brown wire with black connector is supposed to go to a temp sensor mounted on the top right area of the A/C box. This sensor shuts the compressor off if cold air temp not detected which is an indicator of low refrigerant. This is wasn't installed in my car. The boss for the sensor is there but was never drilled out. The parts manual indicates that this is a Buick item.

- The cut orange wire is the heater blower power supply for non A/C cars. The 1979 Product Assembly Manual actually has instructions to cut the wire close to the engine harness and discard the rest of the wire and connector on C60 (A/C) equiped vehicles. A/C cars have an extra wiring harness (goes through firewall under A/C box) which covers the blower etc.

Now I just got the pesky "buzzer" to figure out.

Paul
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Postby 77 Spyder » Wed Jan 24, 2007 10:45 pm

Will your car run the A/C fan on high with the engine off? For some reason I remember that my car would only run the fan on high, if the engine was running. Must have worked through the oil pressure switch?

I could be dreaming, But I though I remember that weird setup.
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Postby acstestinc » Wed Jan 24, 2007 11:09 pm

Never tried that. I check it out.
Paul
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Postby vegatex » Thu Jan 25, 2007 7:39 am

I think both my cars had the cut orange wire. The '77 vega was non-A/C, but the main wiring harness all came out of a '75 Starfire manual shift with A/C, so that explains why it was cut! I'm pretty sure the Sunbird has that also. Since I always associate orange with constant hot battery (like lighter and dome lights), I figured it was some owner mod that had been installed and removed. Thanks for solving that mystery!

Thanks,
Dave
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Postby zeke » Thu Jan 25, 2007 8:30 am

Thanx Paul. now I know what my cut orange and brown wires are. 8)
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Postby acstestinc » Thu Jan 25, 2007 8:33 am

PS: I checked the "cut" orange wire and it is not hot under any condition. A little black electrical tape and it's gone from sight.

The extra brown wire can be disconnected at the plug. You have to pull the contact out and cut it off for a clean job.

Paul
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