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istari
19th February 2016, 04:55 PM
Hello resident gurus,
Apologies for the lengthy post – but I figure more detail means a more likely answer.
I have a 1989 auto Safari (TD42). I have just had a turbocharger and new exhaust system installed by a very reputable company in Perth. On the way home from picking it up I realised that the handbrake warning light was staying on. I’ve never had this problem before.
I did a little research on the forums and understand that this warning light serves 3 functions:

1) Handbrake
2) Brake fluid level
3) Some sort of “vacuum fail indication”?

I have checked the handbrake – it is working fine and the switch and wiring at the lever end are also intact and functioning.
I have the checked the brake fluid level. It is completely full and the float is not sticking.

a) Can somebody clarify what the “vacuum fail indication” is and where the warning light would be connected? Will it be in teh engine bay or do I need to pull the dash cluster out to check?

Some more information – when I was searching under the bonnet I found the solenoid for the A/C idle control. Both wires were connected but the hose on the suction side (driver’s side) was split. I reconnected the hose and the idle increased significantly (from ~700 to ~1300rpm). The turbo installers did not notice this disconnection so they had set the idle based on the unconnected hose. They were going to reset the idle with the hose connected, however we realised that this unit was sucking air regardless of whether the A/C was on or not. I expect that this means the solenoid is broken. I am going to replace this as soon as I can get a new/2nd hand one.

b) Would the faulty solenoid lead to the warning light? I wouldn’t have thought so and the light stays on regardless of whether I disconnect the two wires on the solenoid.

Any info that can be supplied would be appreciated and a photo of where I should look for the failed connection would be even better.
Cheers

the evil twin
19th February 2016, 05:45 PM
If your losing vacuum because of the solenoid/breaks in hoses/etc then, yes, that will be the cause and no, disconnecting the solenoid won't help

threedogs
19th February 2016, 05:51 PM
Chances are you have the original vacuum hoses and with the recent work
they may of cracked from being perished, Replace all the vacuum hoses
its very cheap to do,

istari
19th February 2016, 05:53 PM
Thanks @threedogs and @the evil twin,
Sounds like hose replacement is a good first step.

Is that confirmation that this warning light is a vacuum fail indicator?
Cheers

4bye4
19th February 2016, 05:55 PM
Hi mate - what ET said plus it would be worth checking all your vacuum hoses under the bonnet for damage or not connected properly while you are at it. sounds like one may have dislodged when the work was being done.

MudRunnerTD
19th February 2016, 07:29 PM
I'm surprised your brake peddle is not hard and your clutch a biatch to push in with a vac leak big enough to activate that light?

I had a full split in a vac line under the bonnet and the light didn't come on but the brakes basically failed.

Yendor
19th February 2016, 07:55 PM
As a test try disconnecting the low vacuum switch and see if this turns the light out.

Did you try disconnecting the wires for the low brake fluid?. Did they have the centre console out for any reason?

istari
21st February 2016, 10:55 PM
Hi Yendor and MudRunner,
Brakes and clutch (it's an auto) are both fine so if it is a vac leak it is certainly not a big one.
They did not have the console out during the install. The plug for the low brake fluid was already disconnected from the bottom of the brake fluid cylinder prior to this warning light and replacing it did not fix the problem.
I have fixed the A/C idle solenoid and that wasn't an issue.
Can you tell me where the low vacuum switch is located? Do I have to disconnect from inside the dash console or is there a connection in the engine bay that is easier to get to (as a simple check)?
Cheers,

Col.T
29th February 2016, 06:49 PM
G'day Isty
hate being the dumbest chook in the hen house but have you checked the switch in the centre console?
Hand brake lever is pulled up the pin in the switch is sprung up and the light comes on. If the switch is faulty it could stay on. Surprised it's the hand brake light and brake fluid is involved. Going back to FC Holden days (and before, hand brakes were always mechanical. Guess I've lost the plot. Again.
Luck,Col