Not entirely accurate. My late August '86 has/had the same dealer installed system, yet had the high pressure switch installed. The switch kicked in the HIGH speed on the fan, and shut off the compressor clutch until the radiator temp dropped. Mine was wired to turn the fan on low speed when the A/C kicked in, go up to second/middle speed when the radiator temp switch called for the fan, and High speed was only when the switch called for it or the A/C pressure switch called for it.

There's also a 2nd stage fan relay above the fuse panel that kicks in with the A/C switch turned on. My guess is there are a number of variations in how these systems were installed. I've since completely modified and rewired my system with a custom cabinet and the larger later model evaporator and fans, larger parallel flow condenser, plus an additional fan that blows air forward through the passenger side fresh air duct. I also have a switch to kick in the 2nd stage fan anytime I have to idle with the a/c running. Low doesn't cut it when you're idling at 116F.

Keith Hughes
'86 Westy GenV Turbo (Marvin)

------------------------------

Date: Mon, 29 Jul 2019 09:21:28 -0700
From: vw_van_fan_Mark <madvws@COX.NET>
Subject: Re: Wiring Challenge -- Bentley page 97.68 -- Wire H6 (Rad. Cool Fan
 Thermoswitch)

Ok, since you have an early/mid 86 Westy the A/C system wiring diagram
is not shown in the Bentley. Your retrofit A/C has no pressure switch in
the freon system and thus has no use for the middle fan speed that the
dangling wire was meant to be part of.

As David said, you should determine which size rad fan motor you have so
you can correctly assess any issues with the cooling fan system.

(the 4th digit - 'Z' tells that it is a Westy, the 10 digit - 'G' tells
that it is an 86 model. VW built more or less 12,000 vans per month so
the 51437 tells that was several months into model year production. VW
model year production began in July/Aug most years)

Mark