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Topic: Electrical niggles (Read 578 times) |
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Dav3y
Newbie
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Electrical niggles
« on: May 24th, 2006, 6:52pm » |
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Hello people,
I have just aquired one of these lovely motors from one of your other members. It's a Cossie Estate Facelift.
Have a couple of electrical things I'm in the process of sorting to restore her to fully working spec.
First one is SATC compressor not working. I'm suspecting it needs a regas, but unusually the pressure switches on these seem to kill the compressor on both over and under pressure. Plug had been removed from the compressor as well, but not sure why as it turns by hand o.k. It also seems to have a blue and not a greeen relay fitted on the WOT relay position (R24) which differs from the manual. Are either colour acceptable to work ? The one in there is normally closed type. Also the blower motor goes on and off on manual which doesnt seem right. I'd have a go at repairing the HBC module if they are repairable, but suspect a replacement from the breakers may be worth a try.
Second problem is no heated front screen. I have had the switch out which seems fine. The Relay for the front screen is missing ( R18 ) and i have temporarily nicked one from my Mondeo which seems to be the correct pin outs. The missing relay that feeds fuses 38 and 41 doesn't appear to be getting a control signal from the Central Timer module. Is this module a common fault or unlikely to be the problem as all the other functions it carries out seem to be o.k. ? If i pull both fuses, I am able to read continuity to ground on 41, but not 38, so I'm guessing there is a wiring or earthing problem with the RH side of the windscreen. Anyone know what good readings i should expect to see across the screen wires and whether there is a common ground for both sides or just individual ones ?
The manual says there should be two bridge links in the place of two relays (R22/R23) which are not fitted and i only have one  Could this be causing any of my problems ?
3rd one is the relay (R20) for the Self levelling suspension is missing. I'm guessing this model doesnt have it fitted or someone has replced the shocks and removed it. No biggie there really as I have adjustable lights height.
Anyone have a photo of the inside of their fusebox i can take a look at to see exactly what should be where or can offer me advice on the relays and apparent missing link ?
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sector-9
Senior Member
No scorpio anymore
Posts: 1069
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Re: Electrical niggles
« Reply #1 on: May 24th, 2006, 9:07pm » |
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Either green or blue relays are acceptable for the A/C system - the important thing is they should be n/c type. Pressure switch does indeed stop compressor if high or low. If high it will also run the cooling fans at high speed. Has plug been disconnected or has it just worked it's way loose and finally off? Mine has the retaining catch broken so would do this over several miles; I've now glued it into position 
My diesel saloon had a link missing in position R23 too - I fitted a link from a spare fusebox but it seems to have made no difference so I assume it is needed for a different country (perhaps daytime running lights?). The link in R22 is where the starter inhibitor relay would go on an automatic - I think - you can check this by seeing if the engine will turn over with it removed...
There seems to be a debate at the moment as to whether the estates had electrical or hydraulic self-levelling suspension, or just standard. It appears that all three options are viable though if standard then it is likely that it had self-levellers fitted originally but were too expensive to replace. Obviously the hydraulic system doesn't need the fuses and relays!
Sounds like you have a fault with half of the heated screen. I don't know for sure but I would expect it is separate grounds for each half as the total current draw would need a very thick earth wire. Possibly the previous owner removed the relay (to test something else?), but without a switched feed to the coil windings it won't work anyway. Could be a faulty CTM but do check for continuity between it's multiplug and the two contacts for the relay coil first as wiring problems are not uncommon now these cars are getting old.
Darren
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Dav3y
Newbie
Posts: 10
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Re: Electrical niggles
« Reply #2 on: May 25th, 2006, 8:17pm » |
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ok, thanks for the tips.
Had a final look at the AC tonight, and Im getting 12v up to the pressure switch but the switch is reading open circuit so i have it booked in for a regas tomorrow. Interestingly after reading the electrical guide on the aircon, it makes no mention of switching the WOT relay on as well on a low/high pressure condition so I'll report back after the regas. This switched 12v does get sent back to the PCM for some purpose on the diagram i am looking so guess it gets used for something.
Mine is an auto, so still a little unsure about those two links
Screen is not so good news. There are two wires to each side of the screen, the thick ones seem to be switched live to the fuses and the thinner ones the earths. As well as the relay not being latched, i do have an open circuit on the drivers side  . May have a word with a mate who fits windscreens for a living to see if he has any ideas on how i may be able to repair. Either way i won't bother chasing the possible CTM fault unless i can get the drivers side of the screen sorted as it would be pointless.
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sector-9
Senior Member
No scorpio anymore
Posts: 1069
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Re: Electrical niggles
« Reply #3 on: May 25th, 2006, 11:09pm » |
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It is possible that (if one of those links is for the starter inhibitor relay), that it may be fitted instead of a relay on most automatics since they are electronically controlled gearboxes. I could be totally wrong but perhaps the relay is only fitted to autos with the 2.9 12V or diesel engines as these are not electronically engaged?
The WOT relay just cuts power to the air-con compressor when sent a signal from the ECU (when it senses the throttle is open fully). The output from the relay goes to B9 pos 1 (I think), and pos. 0 goes to the compressor clutch - a short link connects the two...
Darren
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Dav3y
Newbie
Posts: 10
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Re: Electrical niggles
« Reply #4 on: May 26th, 2006, 8:45pm » |
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Well, guess I'll ignore those links as the aircon has been recharged tonight and it's going well.
I can't recommend the guys mentioned and used by Eric on this page http://www.fordscorpio.co.uk/acrecharge.htm enough as it appears i had three seperate leaks appear after the full regas and they spent a good deal of extra time evacuating and recharging 3 times after cleaning the 2 drier joint's and upper condenser joints. Pity they didn't show before the first regas as it would have saved a whole load of time.
It seems the WOT relay is not just a WOT relay, but also acts as a backup to a low/high pressure condition as well as mine was latching constantly and going o/c before the regas and now isn't latching unless the WOT condition is met. Perhaps a slight revision of the fault guide is required ?
Just gotta see if i can sort something with my screen now and I'll be more than happy.
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