soutie Posted July 2, 2023 Share Posted July 2, 2023 Trying to sort out the wiring on my 1989 110 that I am rebuilding. On my heatered rear screen relay I have a wire soldered to the black pink wire. I assume that this should go to earth. Is this a correct assumption. Looking at the wiring diagram for 4 cylinder models 1986 to 1990, there are side diagrams for the rear heated screen with relays, but the others do not match what I have. Looking at the 1991 onwards wiring diagram I can match 4 of the 5 relays that I have by the fuse box. However I can't find one on the diagram. It has a white red wire, white wire, white purple and a white wire. I have a 200 tdi in the 110 and don't have twin tanks. What is this relay for? Quote Link to comment Share on other sites More sharing options...
Paul C Posted July 3, 2023 Share Posted July 3, 2023 Fuel pump relay? Been trying to find it in my loom, as it is supposed to have one but it doesn't exist. White purple is the fuel pump feed. Quote Link to comment Share on other sites More sharing options...
Peaklander Posted July 3, 2023 Share Posted July 3, 2023 Yes it's for a fuel pump and the relay that enables it. You have a 200TDi so it won't be there. This is the V8 diagram. 1 Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted July 3, 2023 Share Posted July 3, 2023 Interestingly that relay appears to cut the fuel pump if the oil pressure switch isn't closed, unless it is cranking. Presume that is for a carb'd vehicle? With EFI that's handled by the ECU of course. 1 Quote Link to comment Share on other sites More sharing options...
soutie Posted July 3, 2023 Author Share Posted July 3, 2023 Thanks for the replies. It sounds like I should leave a relay in there as a spare. Any other ideas? Quote Link to comment Share on other sites More sharing options...
Peaklander Posted July 3, 2023 Share Posted July 3, 2023 20 hours ago, soutie said: On my heatered rear screen relay I have a wire soldered to the black pink wire. I assume that this should go to earth. Is this a correct assumption. Direct-to-earth connections are always black and only black. I can't find any reference to Black-Pink. I don't think it's a colour used. Pink-Black is, but not for you (EGR / Throttle position). 2 hours ago, soutie said: It sounds like I should leave a relay in there as a spare What do you mean? Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted July 3, 2023 Share Posted July 3, 2023 5 hours ago, soutie said: Thanks for the replies. It sounds like I should leave a relay in there as a spare. Any other ideas? Fit a V8 to make best use of the relay? 1 Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted July 3, 2023 Share Posted July 3, 2023 38 minutes ago, FridgeFreezer said: Fit a V8 to make best use of the relay? Agreed. Quote Link to comment Share on other sites More sharing options...
monkie Posted July 3, 2023 Share Posted July 3, 2023 23 hours ago, soutie said: On my heatered rear screen relay I have a wire soldered to the black pink wire. I assume that this should go to earth. Is this a correct assumption. The black pink (BK) wire goes from the heated rear window relay to a diode. I can't find a wiring diagram right now, but I'm sure it's shown of you look at the heated rear window diagram. 1 Quote Link to comment Share on other sites More sharing options...
Peaklander Posted July 4, 2023 Share Posted July 4, 2023 12 hours ago, monkie said: but I'm sure it's shown if you look at the heated rear window diagram. Amazing. You are correct. I dug out the old diagram, which I rarely use and the BK wire is there. The circuit seems to check that there are enough volts available before allowing the heated screen to operate and the diode prevents a back-feed. Quote Link to comment Share on other sites More sharing options...
monkie Posted July 5, 2023 Share Posted July 5, 2023 On 7/4/2023 at 7:55 AM, Peaklander said: Amazing. You are correct. I dug out the old diagram, which I rarely use and the BK wire is there. The circuit seems to check that there are enough volts available before allowing the heated screen to operate and the diode prevents a back-feed. I drew up this chart from when I did my rewiring project: As I understand the circuit for the heated rear window, as you say there is a mechanism to prevent it being turned on unless the alternator is charging the battery. The Black/pink wire goes to a diode, from which a black/slate wire goes to a voltage sensitive switch to prevent the heated rear window from drawing current and draining the battery if the alternator isn't being driven by the engine. Quote Link to comment Share on other sites More sharing options...
monkie Posted July 5, 2023 Share Posted July 5, 2023 A solid colour is from a supply to a switch and a striped colour is switch to component. I have used the standard lucas colour code: G=green, LG = light green, R=red, U=blue, W=white, O=orange, P=purple, N =brown, B=black, Y=yellow, S=slate(grey), K=pink. G fused ignition on GR left turn signal GW right turn signal GP brake lights GN reverse light GB fuel sender GY heater blower motor switch GS heater blower motor switch LGG oil temperature LGW oil pressure sender LGB screen wash pump LGP trailer warning light LGN hazard switch to flash relay R running lights RO right side/tail RB left side/tail RY rear fog RLG wiper motor RW 12v socket illumination U head lights UO right main US left main UK left dip UB right dip UG wiper motor W unfused live ignition on WR ignition switch to starter relay WO ignition switch to heater blower fuse and radio WB rear window heater WS fuel sender to guage WN oil pressure warning lamp WY hand brake warning light WG Heated rear window switch to relay/dash light P unfused permanent live PG fuse to heater blower motor PO seat belt warning light (where fitted) PW interior cab light PU door switch (where fitted) N permanent live from positive terminal bus on starter solenoid NLG wiper motor NY charge warning light NLG flasher relay NW fuse to heated rear window relay B earth BU diff lock engaged warning light BW brake warning light BR hazard switch illumination BK heated rear window relay to diode BS heated rear window diode to voltage sensitive switch YB Glowplug Feed 2 2 Quote Link to comment Share on other sites More sharing options...
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