Radiator fan connections

[the1andonly]

97 4x4 fancy air con
geofs diagram
http://www.g8dhe.net/bwm/bwmanualp.htm?1997/Page_46
now detatched left hand plug ENGINE ON
AIRCON ON OFF OFF OHMS
red blue 9.5V 0V 0
red 13V 0V 0
black 0V 0 0
red brown 1.5V 0V 0
The displayed does not show as clear as the table hope it is understandable
with the aircon on which fan is on, both?
IS the red/blue low speed fan?
is red high speed?
with the left disconnected the rhs was working with air con on.
the engine was only on for a few mins so is red/brown temperature indicator related?

[cmm303]

Fans are wired in parallel, so they should run together.
They have two speeds, normal and high.
Not sure which speed is used for aircon but you can check that the two speeds work:

You can force high speed by disconnecting the lead from the 2-wire engine temp sensor (simulating the sensor going open circuit) - there's a short delay before they come on high speed.
If you stick a 180 ohm resistor across the terminals in this disconnected lead the fans should run at normal speed. (It did on mine, anyway!)
150 ohm or less and the fans go at high speed.
More than 180 ohms but not open circuit and they switch off.

Looking at your wiring colours, could the red brown actually be red black?

[the1andonly]

clean the grime away and yes in a decent bit of light it is indeed red and black.
Thanks
your info will help no end.

[the1andonly]

the sensor is it just above the small hose coming out of the head towards the rear of the engine.
how does it fit, pull or twist.

[cmm303]

the sensor is it just above the small hose coming out of the head towards the rear of the engine.
how does it fit, pull or twist.

Yes, spot on. In this pic it is the connector to the left of the 4 metal pipes, showing just below and nearly masked by the bright red and grey wires, and as you say above a small hose (brown near its clip in this pic). It must pull off, 95% sure. In the photo, you can see at 4 o'clock on the connector one of its retaining clips.


Pic of the sensor from the bongomeister's shop, the connector would go on the LH end in this pic:

[the1andonly]

Thanks
now a monday job. sons motorbike tonight and next weekend, this is the normal fortnightly trip to mother in laws.
Tommorrow is probably prep time for weekend and andy's temp sensor set up. Yes I'll be working on a Bongo but not mine.
thanks again

[the1andonly]

moving the bracket above makes the job easier.
there is a clip at bottom of the connector to depress and pull.
------------aircon open 200ohm 150ohm
red/blue 9.5v --11.8v ---2.6v -----11.6
red--------13v --11.9v ---11.8v ----3.4v


aircon values engine running
I couldn't tell speed of fan by noise

[cmm303]

moving the bracket above makes the job easier.
there is a clip at bottom of the connector to depress and pull.
------------aircon open 200ohm 150ohm
red/blue 9.5v --11.8v ---2.6v -----11.6
red--------13v --11.9v ---11.8v ----3.4v


aircon values engine running
I couldn't tell speed of fan by noise

at the bash and enjoying a sneaky beero, and still struggling to make sense of the numbers. At least I would have expected 150 ohm to give similar results to open circuit but maybe thd failsafe mode is different from high speed. (Hoping for comments from our leccy gurus! Could you try a resistance lower than 150?

Nevertheless I would have expected 3 states to be obvious (but this is a guess): fans off/normal/high. If they were running in all these scenarios we are certainly missing the higher resistance at which the fans switch off.

I'm also a bit surprised it was hard to distinguish between high speed and normal. Makes me wonder if they are only operating at one speed.

[the1andonly]

I thought about running it with 270ohm
but had all ready reconnected and played about for 10 mins and couldn't separate again
havent got 180 by the way.
the red is a large diameter wire
the blue red is smaller.


my intention was to check someone else bongo for fan operation and as a supplement add leds to mine when fans operate.
knowledge is paranonia. (i'm really afraid i can't spell)
i mean power.

[the1andonly]

having just been shouted at about using the wrong tomatoes for me packed lunch
i think you are in a good place
at least 2 more beeros.
As a guess the red is the high speed
the low speed is blue/red @150ohm
It will be a while before i can get down and dirty.
ask geoff if he's there?
( he'll know if hes there)
but has he any comments