Turbo - Engine bay fans

so, I wrote this thread a long time ago, about how the sensors and fans work.
viewtopic.php?f=2&t=1314&p=12307&hilit=fans#p12307.

Today, my fans work, but they dont stay of for 3 mins after engine is switched off.
Actually, I an not sure is they come on at all ???
Rather than run the engine up to temperature, with ignition on, I have jumped the connectors on the sump oil temp sensor which is the one located in the side of the sump. When I jump the turbo temp sensor the fans come on (good). But when I remove this jump, they go off (not what I was expecting).
Any one got any ideas, page 48 of the wiring manual seems rather a collection of connectors?
BTW, when I jump the sump temp sensor, I think I can hear a relay somewhere. It operates on opening/closing this sump sensor.
Wanting to get them operational for Macon.
JohnC?

I thought you were running without the engine cover anyway Simon?

If so one of the fans is largely defunct.

Not really.......because I am routing the air from the fan directly onto the throttle body in centre of vee.
Plus, I will soon be directing some of that air to my turbo, as it it not water cooled......and I wish for some cooling when ignition is off.

"Good. Adaptation. Improvisation. But your weakness is not your technique."

Simon, as you have a 1986 Alp, the rear fan operation is much more complicated than the 1987 onwards Alps.
If that sump switch is faulty or oil temp is below 60 degrees, the fans will not work. As all later models have no sump switch, I would just jumper the sump switch connector permanently.
If you do this, the fans should run at half speed (6 v) the moment you switch on the ign. If this does not happen, there is a problem elsewhere which can only be found by investigation.
If the fans are not running after switching off ign with sump connector shorted, you will have to check out the Timer relay.
I have no practical knowledge of this, but this is what I have understood from the circuit diagrams and 1986 fan operation write up in the manual.
John

John, many thanks, a good plan, especially to have fans on all the time. I will try this out tomorrow.

I have "jumped" the sump temp sensor.
Ignition on, no fans, but I expected them to come on.
Jump the top turbo temp sensor, fans come on, and go off as soon as jumper is removed, but I expected them to stay on for 3 mins.

John, silly question from me, Where in the wiring diagram does it show that they should run at 6v to start with?
From diagram 48, I see relay "13" which I guess includes a timer incorporated inside it?
From diagram S7, relay 13 looks to be under the radio.

For trouble shooting, where would you suggest I start? Where as is what items to verify first? and where physically, not knowing if there are any other controls impacting the circuit....which or off sheet 48.

TIA.

John, silly question from me, Where in the wiring diagram does it show that they should run at 6v to start with?
From diagram 48, I see relay "13" which I guess includes a timer incorporated inside it?
From diagram S7, relay 13 looks to be under the radio.

Simon ..... Firstly, below is a write up of how and when the rear cooling fans operate on the 1986 Turbo. Have a good read of the write up below each diagram, and the other final write up page.
Also there is the circuit diagram which might help you ..... as you can see, it is quite complicated.
Finally ..... for others who might be reading this post, there is the circuit diagram of the 1987 onwards rear fan operation, but there is no write up as the Manual M.R. 273 only explains the 1986 model, so don't think the later models operate in any way like the 1986 type.
Once again, I have no practical knowledge of these Turbos, but this is what I understand from the manuals.









The following circuit diagram is for 1987 onwards.

Of course....... the electrical section of Workshop manual, has a good explanation.
Should have looked there before.
And now I notice that I have a 1989 wiring manual, printed in Dec 1988.

Me thinks I should get myself a 1986 version.

Thanks John.