Electrical guru's--Need help-Window Relay

[ben parrish]

My windows and sunroof stopped working...traced it down to the relay. I pulled the relay and took it apart. I can put a spacer between a contact(picture 1 and 2), causing another contact to make contact and the windows will work. My belief is that there is a capacitor(picture 4) that has gone bad becaue it gets very warm when the relay is energied....reardless of the spacer...but I am really out of my element. Pic 3 is the schematic.

[86 911 Targa]

Originally Posted by ben parrish

My windows and sunroof stopped working...traced it down to the relay. I pulled the relay and took it apart. I can put a spacer between a contact(picture 1 and 2), causing another contact to make contact and the windows will work. My belief is that there is a capacitor(picture 4) that has gone bad becaue it gets very warm when the relay is energied....reardless of the spacer...but I am really out of my element. Pic 3 is the schematic.

Here are a few more pics.

Indeed, capacitors are the "usual" suspects in a failed circuit such as this one.

Although, the relay may have dirty contacts, or is not closing
due to a cold solder joint.

pm me as needed.

Gerry

[dad911]

Relays are simple to test... put 12 volts across the windings, and it should close. Measure resistance across closed contact, it should be nearly 0.

[lucittm]

The role of the capacitor, C1, in this circuit is to quickly charge, in about 1/2 second, when the ignition is turned on. The charged capacitor keeps the relay de-energized. After the capacitor charges, no current flows through it from pin 85 to pin 86 until the door switches are closed which provides a path for the capacitor to discharge and the relay will latch to power the window motors.
The diode, D2, prevents a reverse voltage spike, the inductive kick, when the coil de-energizes and allows the voltage to flow back to ground. The combination of R1 and D4 act as a snubber circuit to prevent arcing across the relay contacts.

dad911, in the post above, describes a relay test but this will not test the function of the shunt capacitor, C1, or the snubber circuits.

Reflow the solder joints on the back of the circuit board and you may solve the problem.

Mark

[Rot 911]

Where is that relay located? I was trying to trouble shoot this a couple of weeks ago and couldn't find it on my '86.

[crustychief]

It is behind the oil temp / pressure gauge.

[86 911 Targa]

Originally Posted by lucittm

the role of the capacitor, c1, in this circuit is to quickly charge, in about 1/2 second, when the ignition is turned on. The charged capacitor keeps the relay de-energized. After the capacitor charges, no current flows through it from pin 85 to pin 86 until the door switches are closed which provides a path for the capacitor to discharge and the relay will latch to power the window motors.
The diode, d2, prevents a reverse voltage spike, the inductive kick, when the coil de-energizes and allows the voltage to flow back to ground. The combination of r1 and d4 act as a snubber circuit to prevent arcing across the relay contacts.

Dad911, in the post above, describes a relay test but this will not test the function of the shunt capacitor, c1, or the snubber circuits.

Reflow the solder joints on the back of the circuit board and you may solve the problem.

Mark

+1

[Lorenfb]

"The role of the capacitor, C1, in this circuit is to quickly charge, in about 1/2 second, when the ignition is turned on."

Since the diagram is totally wrong, the above analysis is also totally wrong,

First, the circuit is a delay timer run off the 'X' pin of the ignition switch
to power the windows after the ignition switch is turned off. Pin 85 goes
to the 'X' terminal of the ignition switch. Second, this relay has a transistor
not shown on the posted erroneous wiring diagram (but on the opened relay
picture), which most likely comprises the delay function with the capacitor.

Bottom line: Before analyzing what could be the problem with the relay,
let's try and post the correct diagram!