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I have a 1987 DD6V92TA Mechanical Engine with a 2 stage Jake Brake system.  Off-Low-High switch, with a High RPM Buffer switch that is wired through the Allison 740 transmission. This system is  set to activate the Jake's when the switch is in either the Low or High position when you let off of the accelerator or you apply the brakes, down to a speed of 15MPH.  I have a 50Amp relay with Diode ordered from DelCity.  Looking from the rear of the coach I presume that the buffer switch is screwed into the governor on the top of the engine with 2 wires attached to it.  I have turned the ignition switch to the on position and used a volt meter to check voltage at the 2 wires at the buffer switch.  No voltage at either terminal.  My question is which of the wires at the buffer switch do I tie into (Left or Right wire looking from the back) with the 50Amp relay to activate the brake lights or do I tie into some other wire some where else.

Fellows thanks for any help as when it comes to this kind of stuff I am as dumb as a box of rocks.

There was a thread in this issue recently,I think LUVRBUS and a few had this going on here;
http://www.busconversions.com/bbs/index.php?topic=13122.0[/url
good luck
  Van (http://www.busconversions.com/bbs/index.php?topic=13122.0)

Hi Eagle,

You have to trace which wire "from the buffer switch" goes to the selonoids under the valve covers. That will be the one activated

when your jakes are on. The buffer switch will only bring on the jakes when 1, rpm's are high enough and 2, when oil psi is high enough.

Most bus company's use amber lights for the jakes. It is only slowing and not stopping, so it makes sence.

Good Luck
Nick-