Water Temperature Switch Wiring

[shadesh]

Hi,

Can someone tell me how to wire the Water Temperature Switch for my car. I have a 1975 280Z. It is a California model,, not sure if that is important.

The wires for the Water Temperature Switch was broken and I am not sure how the original connection was. I believe there are two wires coming out of the Water Temperature Switch.. Black and Red. The black would be grounded?? and the red wire???

I look forward to your feedback. Thanks.

[geezer]

I am looking at a 1975 wiring diagram. You are correct, the black wire is shown going directly to Ground. The red wire for a California model is shown as being spliced into the red wire that runs to the EGR Cut Solenoid. If you have to connect this red wire, pay attention to the diode that is shown on the diagram. The diode allows the current to run in only one direction, so you have to splice in on the proper side of it. It is shown as a blacked out triangle that may be a little difficult to see, but is directly above the splice on the diagram. The second scan explains it's purpose & test proceedures.

[webdawg1]

Here's a link for the FSM (Factory Service Manual) in case you don't have it yet...will probably help you out quite a bit...as it gives you trouble shooting steps/maintenace procedures for the various systems...etc...etc.

http://carfiche.com/manuals023/cars/

webdawg1

[sblake01]

I don't believe it matters which side of the the switch goes to ground as long as one wire goes to ground and the other goes to the solenoid. All the switch does is complete a ground.

[geezer]

I don't believe it matters which side of the the switch goes to ground as long as one wire goes to ground and the other goes to the solenoid. All the switch does is complete a ground.

No, it doesn't matter, other than to confuse the issue and the next guy that tries to decifer it. What does matter is what side of the diode you splice into on route to the solenoid.

[sblake01]

I was assuming that the wires were already there and just broken off at the switch,

[srbigbutt]

What exactly does this switch do. I have it in my 75 Z, which is not a California model but i think my motor is out of a 77-78 Z. I don't have an EGR valve and I have a Water Temperature Switch that has the ground wire broken. What does this affect?

[geezer]

I was assuming that the wires were already there and just broken off at the switch,

Good point Stephen, I never thought of that.

srbigbutt, The wiring diagram I have for 1975 only shows this switch being used in conjunction with the EGR system. The other thing I can think of off hand, a water temperature switch could be used for other than a control device for an EGR valve would be a spark timing control system. You would have to look in the specific model year FSMs to find how else a water temp. switch could have been used for your car. It could be used for input parameters for a number of uses, that I'm not familiar with I suppose. You say the Ground wire is broken, where does the other wire run to?

[shadesh]

If you have to connect this red wire, pay attention to the diode that is shown on the diagram. The diode allows the current to run in only one direction, so you have to splice in on the proper side of it. It is shown as a blacked out triangle that may be a little difficult to see, but is directly above the splice on the diagram. The second scan explains it's purpose & test proceedures.

Which way does the current flow on the red wire that is connected to the E.G.R Cut Solenoid? Does it flow away or to the E.G.R Cut Solenoid?

I am not sure which side of the diode I would connect the wire from the Water temperature switch??? Will I connect the red wire from the Water Temperature Switch to the wire between the E.G.R. Cut Solenoid and the Diode?

[sblake01]

According to Ron's diagram, you'd connect the red wire beyond the diode. The current appears to flow away from the diode based on the direction the triangle is pointing. In other words, soleniod, diode, and connection in that order. Not certain since my 78 doesn't have that but that's how I read the diagram.

[shadesh]

ok.. I will do that.. Thank You All. Another problem solved.

[geezer]

On wiring diagrams diodes are typically shown as triangles or "arrow heads". The current travels in the direction the "arrow" is pointing. So, to answer the question, no the red wire will not be connected between the EGR Cut Solenoid and the diode. Direction of current is actually a decieving thing. A better way of looking at this is to visualize the voltage as being present and not able to pass through the pointed end of the "arrow head", but able to pass from the other direction. Here is another page from the same manual that does not show a diode in the circuit, but it is shown in the wiring diagrams. In the wiring diagram, there is a connector shown at the EGR Cut Solenoid, and if you follow the wire it shows another connector just before the diode. Continuing in this direction, the splice is made after the diode. It should be easy to find the diode & splice location in relation to this connector.

PS - Sometimes the actual configuration of the wiring & components is different from what you will actually find when you work on the actual car. Good luck and let us know how you make out with it.