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4th gen 90 condensor relay fault


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accord 20l i 1990
Hi - new here, mostly used US forums for problems - never realised we had one here - so hello !
1990 saloon 16v 2lt PGM-Fi air con. abs, cruise. F20A5 - CB3

Anyway - condensor fan relay supply voltage - I'm getting no earth when I should have earth.
ie igniton on, air con switch on, temp setting on etc ( I have the full workshop honda manual re page 15-51)

The compressor fan was running when parked up ( after several hrs parked up ! )
So I split the fan plug and left it like that to save the battery ( quite a while back ! )

But now - invetigating it - when re-connected - the fan does not run when I switch on air con - and no air con also.
Condensor fan is good ( runs ) jumped separate wires.
Relay is good ( so long as it IS the one on the right ie furthest from the headlight ) as shown in manual.
Its tight to check wire colours but possible.

The engine fan is working ok - comes on at right temp range etc.
I run at present with the condensor fan disconnected.

My issue is no earth on the feed side of the relay.as measured with a multimeter ?

Something initlally caused the condensor fan to mis-behave - so could have a timer fault, sensor switch fault, diode fault etc.

The trouble shooter says with igntion 2 on, heater reostat on, ac switch on I should have battery voltage across the relay coil side ?
If not - and I do have battery voltage to separate ground ok ( I do ) - then its an open in the neg B wire or open diode.?

Is this the diode between the two relays ? - and if so - what sort is it if its shot ( not available new afik )
Could a generic one be wired in - or are there used supplies ? How would I sort an open on the neg wire -
( just run a new one from ground ? )

I am loathe go too far with this as the car is running fine without the comp fan - and I can exist without air con
( but its rather useful in winter when its wet ) I don't want to mess up the timer unit so the engine fan gets stuffed ?

The wiring diagram page 15-45 confuses me - and I know a fair bit about 12v electrics having a boat -
there seems to be neutrals coming in all directions with diodes etc and connections to cpu/timer etc ?


update - following some lateral thinking and blowing no 7 fuse - I realised on a right hand drive car ( at least on mine ) - the air con relay is the nearest to the front ! Even on left hand drive models - the relays are mounted drivers side, same as mine ( passenger side ).
Now I am checking the right relay - I have sorted the following.

The relay is fine ( tested on bench ) I have 12v to coil side with air con controls on. I have 12v from 15 amp fuse to relay output to fan. I have a good earth on fan. Fan works. BUT - no earth at relay coil when air con controls are on ?

I have now, while changing thermostat - fitted and checked new engine ect temp switch ( 93 c) - fitted new ect switch (108c) air con

With my air con fan re-connected - when I run up to engine temperature ( which is good ) main fan and air con fan come on ?
Is this right ? - I thought only both fans came on when exceptionally hot - or when air con was operating.

The air con will not operate or turn on fan ? Air con does not work with engine running either.

I am suspecting the air con could be low gas/ bad or failed pressure switch ?

So an ideas - much appreciated.
Nice to find people talking about 4th gen accords !
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