Vacuum Switch and Filters

Looks like the switch has gone so it stays at max impedace even with vacuum so flashing 4wd light.

The mice have eaten both little filters.

Switch £80 and filters £10 each.

Can you make filters from foam off a sponge.

Getting at the vacuum switch on a 07 is virtually impossible.


Reading Kirkynuts sticky is tempting!

Just fit a switch, its a piece of p*** to do, I fitted a metal toggle for about £3.

I thought flashing 4wd light meant it does not sense enough vacuum, so that should point to a leaky vacuum system?

Not a piece of piss to do at all. It took ages to get it off. I could then get at the electrical connections which I thought I had got to but it seems not and it did switch to making a circuit at 15kPa bit a below half the 40kPa number in the workshop manual, that's not the problem.

The vacuum reservoir is holding its pressure. Will test the solenoid / vacuum valves for leakage next.

I can find no leaking flexi tubes.

The across the axle metal tubes were new in the summer so will check again but they should be fine

There are three filters one on the vacuum switch and one on each of the two solenoids/ vacuum valves.

They are relitivly small and not made of much. One is not eaten by the mice.

auchenblae wrote: Can you make filters from foam off a sponge.

I should think so, as I understand it the filters are there to damp out pulses in the vacuum, if you can find some similar foam then it should work OK.

There should only be 2 filters, one on each solenoid valve.

They are to stop water, dirt and dead things getting into the vacuum lines, so anything that lets air through will do.

(When you apply vacuum to one side of the hub, air goes into the other side, to push it over, through one of the filters.)

The third filtery thing is likely the non return valve in the line from the manifold to the vacuum tank.

About the switch, all I did was cut the wires to the switch, shove them back into the car and attach to a toggle?
Apologies if it's different on yours?
The switch on mine just goes to earth telling the control box to do vacuum stuff.

troggy wrote: About the switch, all I did was cut the wires to the switch, shove them back into the car and attach to a toggle?
Apologies if it's different on yours?
The switch on mine just goes to earth telling the control box to do vacuum stuff.

I get your logic and am tempted to do just tht but not just yet. The switch is working but I may test the system with the wires shorted.

I have a set of solenoids and a vac sensor

Yes I see, as mine is an 02 and the vac system is about shot anyway I didn't have much to loose. As it is I have a sexy 'lock' toggle which locks the hubs but won't unlock as most of the rest is rotted through.
If I can be ars** when it's a bit warmer I might reroute the whole vac system through the engine bay and drop down each side. Or sell it and get a newer one!

Would be tempted to buy them off you j999pre?

facade wrote: There should only be 2 filters, one on each solenoid valve.

They are to stop water, dirt and dead things getting into the vacuum lines, so anything that lets air through will do.

(When you apply vacuum to one side of the hub, air goes into the other side, to push it over, through one of the filters.)

The third filtery thing is likely the non return valve in the line from the manifold to the vacuum tank.

There are three filters one on each solenoid valve and one on the vacuum switch, No idea what the one on the vacuum switch does does as the vacuum switch will hold a vacuum for a few hours.

There is no filter on the check valve which is working to spec.

There is only a voltage to one solenoid valve at a time. and with no voltage on the other solenois there is no path between the hub side of the valve and the check valve or filter pipes.

With no voltage on the solenoid there is a path between the check valve input and the filter.

Therefore if there is voltage to the disengage valve there is a vacuum at that side of the hub but the engage solenoid valve is closed so there is route for air to get out the filter.

I proved that by putting pressure on the hub side of the solenoid valve with no voltage applied to the solenoid and it held until I connected 12 volts to the solenoid valve.

The Suzuki workshop manual also advises that with no voltage the only path on the solenoid valve is from the check valve tube to the filter tube.

The filter on the engage solenoid valve has been eaten away by mice and if you blow through the check valve input tube on the solenoid valve wih a good filter some air leaks out the filter, on the engage valve which s easier to blow through due to the eaten away filter I assume that it cannot be helping to keep the vacuum up to specs to engage the hub so it may be a part of thhe flashing light problem but once more into the diagnostics.


eddie