Re: Thermo Time Switch

[DMCVegas@xxxx]

YES! It does mater which way the wires are plugged into the thermo 
time switch. When looking at the schematic of the tt switch and the 
cold start valve, you'll see that both are connected together with 2 
wires, and that the tt switch also has a ground connection. Plus the 
cold start circuit is tied into the starter, so this circuit will 
only be active durring engine cranking.

The way the circuit works is like this: The hot wire first connects 
to the cold start valve, and then connects over to the tt switch. 
When the coolant is below a certain temp, there is an armature inside 
the switch witch grounds itself. This ground connection completes the 
circuit for the coldstart vavle to fire. The internal heater inside 
the switch simply grounds itself thru the switch casing. This way if 
your car doesn't crank within a certain amount of time, the arm heats 
up and opens the circuit to stop the cold start valve.

If you had a cold start relay installed, the relay connections would 
have to be modified. The cold start valve would then be grounded thru 
the same connection the relay is grounded thru to complete the 
circuit.

The reason the circuit is set like this is because it is unsafe to 
ground electricity to a fuel line.

So, if you were to swap the 2 wires that go into the tt switch, the 
cold start valve would fire every time your cranked the engine. If 
the valve fires when the engine is warm, it can flood. If there is a 
related issue with the engine keeping it from starting, it can pose a 
possible fire hazard.

-Robert
vin 6585



--- In dmcnews@xxxx, "Rob van der Veer" <rob.van.der.veer@xxxx> wrote:
> Dear List,
> 
> I've been breaking my head on the schematics of the thermo time 
switch. I've
> been reading the workshop manuals..
> 
> My question is this: is the connector (from the wiring harnass to 
the actual
> tt-switch) symmetric or does it matter which way it is connected?
> 
> I'm in doubt whether it is connected correctly.
> 
> Yours,
> 
> Rob.
> VIN3695