An electrical nightmare!
Discussion
Hi
I have just been doing some work on the wife's 280i, trying to go through some of the fault's I know off on it before BBWF!
Did most of them and found another couple which need some attention, but one is causing us some concern.
I have two fix's for it but they are a bit extreme, so I am posting this up hoping somebody can help so it can be fixed correctly!
The problem is there is a electricl power drain on the system when the ign is turned off.
We traced it to a relay which in the bible says LH Brake warning light num 108. Which it's not it appears to be the fuel pump relay? It is on all the time,(The fuel pump is not) thus the power drain and it get's hot and could be a fire hazard! We can see a way round the problem but as I said it's a bit extreme.
The relay is a standard one and it has 5 treminals on the back. Three in the middle and two either side. The top middle one is marked 87 and has a Black/yellow wire. the middle/middle one is 87a and has a White/black wire, the bottom middle is 30/51 and has a White wire, the left side is 86 and has a Brown wire, and finaly the right side is 85 and has a Black wire.
The brown wire is powering up the relay all the time! The middle wire (White/black) appears to be extra compared with all the other relays, they usual only have four wires?
Has anybody come across this before, or has any body got a wiring diagram for a 88 280i. The bible's diagram doesn't help!
Thanks
Andy.
I have just been doing some work on the wife's 280i, trying to go through some of the fault's I know off on it before BBWF!
Did most of them and found another couple which need some attention, but one is causing us some concern.
I have two fix's for it but they are a bit extreme, so I am posting this up hoping somebody can help so it can be fixed correctly!
The problem is there is a electricl power drain on the system when the ign is turned off.
We traced it to a relay which in the bible says LH Brake warning light num 108. Which it's not it appears to be the fuel pump relay? It is on all the time,(The fuel pump is not) thus the power drain and it get's hot and could be a fire hazard! We can see a way round the problem but as I said it's a bit extreme.
The relay is a standard one and it has 5 treminals on the back. Three in the middle and two either side. The top middle one is marked 87 and has a Black/yellow wire. the middle/middle one is 87a and has a White/black wire, the bottom middle is 30/51 and has a White wire, the left side is 86 and has a Brown wire, and finaly the right side is 85 and has a Black wire.
The brown wire is powering up the relay all the time! The middle wire (White/black) appears to be extra compared with all the other relays, they usual only have four wires?
Has anybody come across this before, or has any body got a wiring diagram for a 88 280i. The bible's diagram doesn't help!
Thanks
Andy.
Edited by Mr Tank on Sunday 4th July 19:40
Edited by Mr Tank on Sunday 4th July 19:47
Well the 'extra' wire just means that the relay switches the incoming feed from one circuit to another, but that wouldn't be likely on a fuel pump - it'd be either on or off.
The relay having a permanent feed on the (85 or 86) is the concern, sounds like something is stuck or faulty for that to be happening. Airflow meter kill switch stuck?
The relay having a permanent feed on the (85 or 86) is the concern, sounds like something is stuck or faulty for that to be happening. Airflow meter kill switch stuck?
The fuel pump relay is what is called a run start relay if I remember right. My car is at the shop getting its relays replaced. It is not the same as the other relays (Ford number not a Bosch relay). The extra wire is coming from the starter which provides a hot when starting the car. The other hot is from ignition which will keep it powered while the car is running. Sounds like someone put a regular relay in there or has power coming to it all the time.
The Airflow meter kill switch being stuck on has been mentioned. It's located on the metering device where the flap is. Look around there and ther should be a wire plugged into it. On mine it's adjacent to the wing. Unplug it and see if the power cuts off. Though is switched on all the time and doesn't drain the battery.
I've had a look at my relays and can't work out which is which. I'll have another try tomorrow.
I've had a look at my relays and can't work out which is which. I'll have another try tomorrow.
Series 1.5 USA 280 here....
I pulled 108...it is a five pin relay (coil and change over contacts.)
The diagrams in the bible are (I think) taken from the TVR diagrams that are in the manuals that went with USA cars, they appear to be direct copies of the ones in our manuals.
Any way...looking at the diagram for a series 2 (86 onwards) the operating coils tags 85 & 86 are common on relays 108 and 109. That would indicate a relay problem. I assume you have swapped 108 & 109.
A brake warning relays operates one of two ways, 1. it indicates a blown brake light, 2. it operates from a pressure sensor in the brake line, as there are two I would guess it is to indicate a blown brake light. So try removing your left brake light bulb and see if relay releas.
But as there appears to some doubt as to whether 108 is actualy 108
I would approach it by putting a test lamp probe into the 85 or 86 of the relay and pull one fuse at a time til the testlamp goes out. That will put you onto the correct circuit
I pulled 108...it is a five pin relay (coil and change over contacts.)
The diagrams in the bible are (I think) taken from the TVR diagrams that are in the manuals that went with USA cars, they appear to be direct copies of the ones in our manuals.
Any way...looking at the diagram for a series 2 (86 onwards) the operating coils tags 85 & 86 are common on relays 108 and 109. That would indicate a relay problem. I assume you have swapped 108 & 109.
A brake warning relays operates one of two ways, 1. it indicates a blown brake light, 2. it operates from a pressure sensor in the brake line, as there are two I would guess it is to indicate a blown brake light. So try removing your left brake light bulb and see if relay releas.
But as there appears to some doubt as to whether 108 is actualy 108
I would approach it by putting a test lamp probe into the 85 or 86 of the relay and pull one fuse at a time til the testlamp goes out. That will put you onto the correct circuit 
have seen a lot and owned certain kitcars which had been re-wired from "specialists" by order of the former owner.
the cables had been new...the rest was a nightmare...the terminals, connectors, the way "how" it was wired, tidyness, electric drawing.....nearly everything of these basic matters were missing or carried out in a bad way!!!
keep the original wiring and search the fault.
the cables had been new...the rest was a nightmare...the terminals, connectors, the way "how" it was wired, tidyness, electric drawing.....nearly everything of these basic matters were missing or carried out in a bad way!!!
keep the original wiring and search the fault.
JVaughan said:
re-wiring ... how much is that going to cost ? are you doing it or is it being done for you ?
having a new loom made by premier looms and dulfords are fitting it, all for under a grand, should have no more electrical problems, the lights would not pop up, i had earth wires glowing in the dark ( it was a fireball waiting to happen)Rob
Gassing Station | Wedges | Top of Page | What's New | My Stuff