Discussion
I have got problems with one fan 1 and fan 2 and horns not working the fuse box is a 97 - 98 with relays separate for each fan and horns as shown in diagram fans work when crossed over one at a time i have had it checked out by diagnostics there is no power running into fan 1 and horn i am told it could be the fuse box unless investigated further has anyone had the same issue.
Me me me !
Exactly the same symptoms on a 97 Chim 4.0, all fuses OK and new relays M0404 type, I have also had the steering boss off to check the earth contact ring, today I ran a fly wire directly from the battery to each of the horns to confirm they were not dead,so in essence all system works but yet no power to fan 1 ( but works when crossed over to fan 2 feed ) - did you ever get an answer and does anybody know the answer as I'm overdue an MOT and at this rate am going to put in my own circuit
Exactly the same symptoms on a 97 Chim 4.0, all fuses OK and new relays M0404 type, I have also had the steering boss off to check the earth contact ring, today I ran a fly wire directly from the battery to each of the horns to confirm they were not dead,so in essence all system works but yet no power to fan 1 ( but works when crossed over to fan 2 feed ) - did you ever get an answer and does anybody know the answer as I'm overdue an MOT and at this rate am going to put in my own circuit
Gary, you have probably already done this, but for others reading this, when the fans stop working on this age of car, the first thing to do is to check the obvious. Get the car hot (just idle it for a few minutes) and watch for the fans to cut in.
If one cuts in, but not the other, then find the cables under the rad. There is a connector in the middle of each cable, pull each apart and clean up the connectors. 9 times out of 10 that is the problem.
If neither cuts in, check the connectors first, but if nothing still works, it could be the otter switch (thermostatic switch). This is a brass plug with two leads attached. On later cars it is inserted into the back of the radiator, passenger side. On early cars it is inserted into the bottom of the swirl pot.
Pull the leads half off the terminals, but leave them attached, and use a screwdriver blade across the bare terminals to short out the switch. If the fans come on, it's the switch that is faulty. If only one fan comes on, the switch is still faulty, but the wiring to the other fan is also faulty. An otter switch is about £12 from a motor factor, you want one that comes on at about 92degrees and goes off again at about 85 degrees. You will also need a big socket. I think it's about 27 mm from memory.
If one cuts in, but not the other, then find the cables under the rad. There is a connector in the middle of each cable, pull each apart and clean up the connectors. 9 times out of 10 that is the problem.
If neither cuts in, check the connectors first, but if nothing still works, it could be the otter switch (thermostatic switch). This is a brass plug with two leads attached. On later cars it is inserted into the back of the radiator, passenger side. On early cars it is inserted into the bottom of the swirl pot.
Pull the leads half off the terminals, but leave them attached, and use a screwdriver blade across the bare terminals to short out the switch. If the fans come on, it's the switch that is faulty. If only one fan comes on, the switch is still faulty, but the wiring to the other fan is also faulty. An otter switch is about £12 from a motor factor, you want one that comes on at about 92degrees and goes off again at about 85 degrees. You will also need a big socket. I think it's about 27 mm from memory.
Gary,
Are you saying that there is no power to the high current feed on fan 1?
I have a S plate 450 and I had the fusebox off last year to sort out some crappy DIY mods to the fan relays.
I think that I found that the high current feeds are separate (i.e. individual feeds for each fan) each with it's own fuse (and the feed to the otter switch on the fuse for Fan 1), but the low current side is common and fed from the otter switch on the rad.
If there is no high current feed then I'd suggest a blown fuse.
Dave
Are you saying that there is no power to the high current feed on fan 1?
I have a S plate 450 and I had the fusebox off last year to sort out some crappy DIY mods to the fan relays.
I think that I found that the high current feeds are separate (i.e. individual feeds for each fan) each with it's own fuse (and the feed to the otter switch on the fuse for Fan 1), but the low current side is common and fed from the otter switch on the rad.
If there is no high current feed then I'd suggest a blown fuse.
Dave
Thanks chaps but that doesnt answer the no power feed to the horn,losing fan 1 and the horn points to a bad relay but as yet I have assumed that the new one I just put in is good - never the less I will be spending the afternoon checking I have a power supply to those pins on the fuseboard.
Things to rule out
Not the connectors under the fans as when fan 2 crossed with one it works
Otter switch contacts cleaned with wire wool
Horns checked with a flylead from battery
Horn contact ring and pin clean,and earth connected to contact pin
Bad lower back from being upside down in footwells confirmed !
I think I'm getting to the point of pulling that board out - is the mounting nut captive ? or will I unbolt and then here it drop?
Things to rule out
Not the connectors under the fans as when fan 2 crossed with one it works
Otter switch contacts cleaned with wire wool
Horns checked with a flylead from battery
Horn contact ring and pin clean,and earth connected to contact pin
Bad lower back from being upside down in footwells confirmed !
I think I'm getting to the point of pulling that board out - is the mounting nut captive ? or will I unbolt and then here it drop?
Thanks Peter but earth should be OK as the horns sounded when I put a lead from battery positive to the horn itself, never the less I will give it a go as I just realised I'm giving it a full battery shunt to do that,just about given up,going to talk to Ian at torque rvt tomorrow,it was such a nice bank holiday!!!! Doh !
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