Disco 1 No power to blower or window footwell relays

94 300tdi Disco

I'm really stuck here so any help would be awesome.

The footwell relay for the blower blew a while back. After I replaced it, it blew again after about an hour. Since it has blown, there is no power getting to terminals 85 & 86 when the ignition is on. This has also happened to its neighbouring relay, the window relay.

Terminals 87 & 30 are getting 12.8v as they should with ignition in any position.

I can't find anything between the ignition and these relays. I'm no expert and relied on logic and a little help from forums so far. I assume there must be some sort of fuse somewhere. All fuses in the two boxes have been checked and are ok.

Cheers.

Ok, now the car won't start. Ignition is dead. When I turn the ignition, there is full draw on the battery (my battery gauge goes down), but there is no life. Not sure what could have caused this to suddenly happen as all I've been doing I'd voltage and continuity tests.

One thing I have noticed is that the earth for the blower is showing some resistance, about 0.7 where the earth for the Windows is showing lowest resistance (same ground location).

The green relay that sits with these two relays also has no voltage to 85 & 86 with ignition on. What is this green relay for? Ignition?

So to summarize all three relays in the driver's footwell are not getting power. Everything that isn't to do with these relays is working as it should. These three relays must have something in common. They are on the same loom from what I can see.

Getting desperate now.

Download this http://www.landy.ee/manuals/electricity/Disco_Elec.Troubleshooting Manual - LRL0077ENG (1997).pdf and follow the feed path according to the diagram , did you check the fuses for continuity or just eyeballed them cos that might misslead you if theres a hairline crack in the fuse

If your not getting any power to the heater blower and the fuse is okay then check the switch.
Still don't see why u say u have a window relay as the 300 series doesn't have them, it has an ECU instead.

sierrafery said:

Download this http://www.landy.ee/manuals/electricity/Disco_Elec.Troubleshooting Manual - LRL0077ENG (1997).pdf and follow the feed path according to the diagram , did you check the fuses for continuity or just eyeballed them cos that might misslead you if theres a hairline crack in the fuse

Click to expand...

Cheers. I checked them as you said as I've been tricked before. Cheers for the link. The good news is, the engine is running again. Looks like I've been getting a bit confused with which relay does what. The middle yellow one which I thought was for the windows is in fact for the ignition so the reason it was showing zero volts when the ignition was on is because it doesn't get a feed until you turn to start.

So with that, I am assuming the green relay is for the windows, hopefully your link will tell me. The seemingly bad earth for the blower is now suspect. Perhaps it shares the same earth as the windows. The rear ones have been dodgey for a while now.

Thanks

discool said:

If your not getting any power to the heater blower and the fuse is okay then check them switch.
Still don't see why u say u have a window relay as the 300 series doesn't have them, it has an ECU instead.

Click to expand...

It's a 94 300. Afaik, its pre ecu and the ecu was introduced post 94?

have yu checked the heater resistor pack?

The Mad Hat Man said:

have yu checked the heater resistor pack?

Click to expand...

It's definitely an issue at the relay end. If I do away with the relay and bridge 30 & 87, I have a fully functional heater. All settings and recycle. I could just set up another relay with a switch and tap into another 12v feed for the relay... It just means id have to switch the power to the blower on and off manually... But I'd rather not.

Larry365 said:

It's a 94 300. Afaik, its pre ecu and the ecu was introduced post 94?

Click to expand...

Ok pre-March 1994 then, so now we know we know what electrical diagrams to look at.
So very simples the 12v supply is from the ignition switch to the blower relay via the fuse. The ignition switch gets its supply from the under bonnet fusebox as does the window switches and relays.

Land Rover's wiring diagrams are a load of nonsense, okay for LR trained engineers maybe but that's it. I'm an electric engineer and never seen anything like them if that style of drawing was presented to me today I would reject them... but then they were produced back in the 1990s

Larry365 said:

It's definitely an issue at the relay end. If I do away with the relay and bridge 30 & 87, I have a fully functional heater. All settings and recycle. I could just set up another relay with a switch and tap into another 12v feed for the relay... It just means id have to switch the power to the blower on and off manually... But I'd rather not.

Click to expand...

Your bridge is just taking the place of the relay contacts, so that's as it should be, but if your sure u have a functioning relay then as I said before check your switch.

I've made some progress, if you can call it that.

I have figured out what the 3 relays in the driver side kick panel are for. The green one is for the windscreen wipers. The middle yellow is for the startermotor and the end yellow one is for the blower (and occasionally the windows).

When bridging the two contacts (doing the relays job) I get a fully functional heater but no windows. By some sort of freak accident, I was moving the relay socket while the relay was in and everything suddenly started working; windows and blower.

I gently place the relay back on the floor and everything carried on working. I then picked it up again and it stopped working, twisted the relay around and it started working again. So this meant that either the relay socket was faulty, or some cable within a few inches of the relay socket was dodgy. I held the wires still a few inches away from the relay and moved the relay around, things were working, so i deduced that it must be the socket.

I chopped the socket off and put new contacts on. At first nothing worked, then jiggling the brown live feed, things were intermittently working.

So I've made some progress but I am now more confused. I have checked earths thoroughly, to multiple places in the car. Earth blocks to battery, to engine, to body work. Everything is earthed. This live feed seems problematic but only within the last 2 inches of it.

I have checked the ignition. All show 12.7 volt when ignition is in which ever position it needs to be in. So power is definitely leaving the ignition.

Completely stumped.

To add more, I appear to have some other gremlins. If I remove the BIG 60amp fuse for the "w-lift, cdl, rear blower" located under the bonnet (it looked suspect), my wipers turn themselves on. If I turn the wipers on full speed, my sidelights turn on..... I've put it back and everything goes back to normal.

With this mentioned, I'd agree that it all points towards bad earths, but I have checked the earth blocks.