First the adjustment. When the throttle comes on or off idle you should hear a faint click. There
should be no other noise coming from the switch during throttle travel, it only clicks when coming on
or off idle. If it does not click you can adjust the switch by loosening its mounting bolts and turning it.
Adjust it so that as the throttle closes you hear the click just before the throttle plate reaches its idle
stop. If you can't get it to click you probably need a new switch although it's possible it's just too faint
to hear it so proceed with the next checks before buying a new one.
You will need your ohm meter for this procedure. Remove the Bosch electrical connector from the
throttle switch being careful not to damage it. If you don't know how to remove Bosch connectors go
up to Step 2.5 and read the procedure. Move the harness connector out of the way and DO NOT
TOUCH IT with the ohm meter. Now look at the switch's electrical terminals. There are three of them
arranged vertically. The top one is terminal #3, the middle is #18 and the bottom is #2. Hey I didn't
number these things, if I did they would have been 1,2,3 from top to bottom. Now with the throttle
closed you need to check the resistance between terminals 2 and 18. The resistance should be zero.
Now with the throttle still closed check the resistance between terminals 3 and 18 and resistance should
be infinite. Next we have to do the same checks at full throttle. Have a friend hold the throttle fully
open. Check resistance between terminals 2 and 18 and you should read infinite resistance, the opposite
of what you had at idle. Check resistance between 3 and 18 and it should be zero. If you do not get
these values try adjusting the position of the switch, sometimes just a little adjustment will fix
everything. If you can't get the correct resistance values by adjusting it you probably need a new
switch. Unfortunately you may need to adjust this switch again if you adjust the throttle's idle stop
which you may have to do later in order to get the idle just right