Wiring Diagram & Fuse Box/Oil Pressure Buzzer

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Herm
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Wiring Diagram & Fuse Box/Oil Pressure Buzzer

Post by Herm »

Hi,

I have a 1990 California and looking for a wiring diagram? I can't see to find one anywhere. I'm having trouble with indicators not working (they were prior to having front resprayed) he took out the dash now I'm left without indicators and hazards. Also the oil pressure buzzer is constant so I need to work out how to fix this issue. 

Any help would be much appreciated. 

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AngeloEvs
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Re: Wiring Diagram & Fuse Box/Oil Pressure Buzzer

Post by AngeloEvs »

There is a post a few down from this one title “offside indicators not working” which may be of help. Regards the buzzer, is it sounding with engine idling?

Normal operation of the buzzer is when the high oil pressure switch opens and the engine exceeds 2000 RPM. If yours is sounding with engine below 2000RPM then it sounds like the Dynamic Oil Pressure circuit in the speedo may be the cause. There is a 6 pin connector which is part of the plastic membrane circuit that may need to be checked or you may have to disconnect it until you find the problem. However, disconnecting the DOPS will stop the oil pressure LED from working as well as the buzzer.

If the buzzer only sounds above 2000 RPM the check the condition of the wiring to the high oil pressure switch which is located near the pulley (WBX’r). If ok, visually check the condition of the 14 copper connections that make contact with the white 14 way dash connector. This is best done with dash removed and the black plastic connector surround unclipped so that you can clearly see if any are damaged.
1987 DG Karisma LPG with remodelled interior

Herm
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Re: Wiring Diagram & Fuse Box/Oil Pressure Buzzer

Post by Herm »

AngeloEvs wrote: 03 Jul 2021, 21:25 There is a post a few down from this one title “offside indicators not working” which may be of help. Regards the buzzer, is it sounding with engine idling?

Normal operation of the buzzer is when the high oil pressure switch opens and the engine exceeds 2000 RPM. If yours is sounding with engine below 2000RPM then it sounds like the Dynamic Oil Pressure circuit in the speedo may be the cause. There is a 6 pin connector which is part of the plastic membrane circuit that may need to be checked or you may have to disconnect it until you find the problem. However, disconnecting the DOPS will stop the oil pressure LED from working as well as the buzzer.

If the buzzer only sounds above 2000 RPM the check the condition of the wiring to the high oil pressure switch which is located near the pulley (WBX’r). If ok, visually check the condition of the 14 copper connections that make contact with the white 14 way dash connector. This is best done with dash removed and the black plastic connector surround unclipped so that you can clearly see if any are damaged.

thank you very much! 

Herm
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Re: Wiring Diagram & Fuse Box/Oil Pressure Buzzer

Post by Herm »

AngeloEvs wrote: 03 Jul 2021, 21:25 There is a post a few down from this one title “offside indicators not working” which may be of help. Regards the buzzer, is it sounding with engine idling?

Normal operation of the buzzer is when the high oil pressure switch opens and the engine exceeds 2000 RPM. If yours is sounding with engine below 2000RPM then it sounds like the Dynamic Oil Pressure circuit in the speedo may be the cause. There is a 6 pin connector which is part of the plastic membrane circuit that may need to be checked or you may have to disconnect it until you find the problem. However, disconnecting the DOPS will stop the oil pressure LED from working as well as the buzzer.

If the buzzer only sounds above 2000 RPM the check the condition of the wiring to the high oil pressure switch which is located near the pulley (WBX’r). If ok, visually check the condition of the 14 copper connections that make contact with the white 14 way dash connector. This is best done with dash removed and the black plastic connector surround unclipped so that you can clearly see if any are damaged.

Hi again, sorry didn't respond to you question. Yes, it's buzzing when it's idling. I have the dash out now and disconnected the plastic membrane circuit, amazed at just how fragile that looks! Could it be a case of faulty oil pressure switch? 
Though I did disconnected to wire to the from the oil filter and the buzzing continued. Though as mine is a 1990 there should be two switches? 

Regarding the indicators, again could it be a faulty relay causing the issues? I'm not much of an electrician so it's a bit of a minefield! 

Thanks again.

 

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AngeloEvs
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Re: Wiring Diagram & Fuse Box/Oil Pressure Buzzer

Post by AngeloEvs »

Was it just the instrument cluster dash pod or the entire dash that was removed, also, is you engine Diesel or Petrol?
1987 DG Karisma LPG with remodelled interior

Herm
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Re: Wiring Diagram & Fuse Box/Oil Pressure Buzzer

Post by Herm »

AngeloEvs wrote: 04 Jul 2021, 19:36 Was it just the instrument cluster dash pod or the entire dash that was removed, also, is you engine Diesel or Petrol?

I believe the entire dash was removed as he had to weld inside and didn't want anything to catch alight. I have a 1.6 diesel. I have a 1990 California. 

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AngeloEvs
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Re: Wiring Diagram & Fuse Box/Oil Pressure Buzzer

Post by AngeloEvs »

There is only one flasher unit marked 21 and located in the fusebox and this operates emergency and normal flasher use.  With the whole dash having been removed it seems the most likely cause of your loss of flashers is a wire that has become disconnected at the rear of the fusebox or some other location en route or at the flasher stalk.
Look for wires with colour codes White, Black/White/Green, Red/White and Black/Blue and check that these are all connected at the fuse box, the Black/White/Green is the 12V feed from the flasher unit to the flasher stalk  and the White  is the 12V feed to the flasher unit so important that you test what voltages you are actually getting .   Also check two fuses in the fuse box  - S4 and S19, if you remove the fusebox cover you will see the fuse description printed into the plastic.

The problem with the Buzzer is more difficult to pin down as it should not sound unless  the high oil pressure switch is not making contact with chassis earth and the engine is at or above 2000RPM - theoretically it seems like a fault with the DOPS circuit in the speedo but since the dash has been removed it could be a completely bizzare wiring fault.    

Untill the exact cause is located you can by-pass the DOPS circuit to enable the oil pressure LED to function by adding a resistor across the the DOPS socket as shown below, any value between 470 ohms and 1k5 (1500 ohms) at 1/8th or 1/4 Watt is fine and they cost pence on EBAY - this will connect your oil pressure LED directly to the low pressure oil switch, this was how all early T25's were wired before the DOPS system (Buzzer of Doom) was introduced around 1986.
Image

 
1987 DG Karisma LPG with remodelled interior

Herm
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Re: Wiring Diagram & Fuse Box/Oil Pressure Buzzer

Post by Herm »

Thank you so much, this is very helpful for me. I have my dad coming down to help out so hopefully we can get it sorted. I really appreciate the time and effort you are putting in to help. Most things I can sort, though electrics are my achilles heel.

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AngeloEvs
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Re: Wiring Diagram & Fuse Box/Oil Pressure Buzzer

Post by AngeloEvs »

Another approach to test the DOPs pcb is to locate the high oil pressure switch ( you should have two oil pressure switches set to operate at different pressures) and remove the wire then connect it to a good chassis earth point, then locate the W terminal on the Alternator and remove the connection. The DOPS will no longer have the two important things it needs to trigger the buzzer, if it continues to sound I would consider the DOPS pcb as being faulty and by pass it as suggested in my last post.
1987 DG Karisma LPG with remodelled interior

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