Relays

[poleonpom]

My fan blower comes on and off as it desires and I thought it can't be a bad idea to change the relay.

I know very little about electronics; am I right in thinking that you can replace the existing relay with a more robust relay? how are they rated and where can I find a replacement?

[p38arover]

What year P38A?

Do you get the HEVAC chequebook symbol?

There was an issue with early P38As having the fans switch off due to a faulty connector at the blower motor. I've discussed this before.

http://www.aulro.com/afvb/p38a-range-rover/122884-need-p38-c-specialist-melbourne-post1428309.html#post1428309

Also have a look at http://www.aulro.com/afvb/p38a-range-rover/49221-p38-rangie-air-con-problem-3.html

[poleonpom]

It's a 1996.

The reason I'm focused on the relays is because one of the fan relays is showing signs of overheating (scorching) and I want to swap it out before it ruins the fuse box

[p38arover]

RL7? Replace it. Also check the fuel pump relay RL12 if I recall correctly.

[poleonpom]

Where do I find replacement relays, how are they rated?

[Scouse]

It's a 1996.

The reason I'm focused on the relays is because one of the fan relays is showing signs of overheating (scorching) and I want to swap it out before it ruins the fuse boxChances are, if it's the original, that the fusebox will be on it's last legs too.

Ron hasn't had too many issues with his but then again it spends more time off the road than on lately :wasntme:. I replaced mine recently after a meltdown.

[poleonpom]

Where do I find replacement relays, how are they rated?

Can anyone answer this?

[wayneg]

LAND ROVER YELLOW RELAY YWB100112 GENUINE NEW | eBay (http://www.ebay.co.uk/itm/LAND-ROVER-YELLOW-RELAY-YWB100112-GENUINE-NEW-/300524426332?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item45f8a6d45c)

[poleonpom]

So, am I right in thinking it's ok to swap like for like? Is there no "beefed up" relay alternative so that the replacement doesn't overheat?

[wayneg]

Relays are rated in amps. Not sure what the genuine one are but they have lasted a decade or more so they cant be that shabby. A bit of reading suggests Bosch / Siemens are 70 amp so thats heavy duty from the start. ( correct me if I am wrong please )
Here are some 80amp peak 5 pin ones, Most aftermarket seem to be 40. Just need to chose 4 or 5 pin. Yellow 4 Green 5pin

(4) Heavy Duty 70A 80A 12V Auto POWER Relays 5 Pin SPDT | eBay (http://www.ebay.com/itm/4-Heavy-Duty-70A-80A-12V-Auto-POWER-Relays-5-Pin-SPDT-/150709269888?pt=Motors_Car_Truck_Parts_Accessories&vxp=mtr&hash=item2316f8f580)

http://www.ebay.com/itm/Car-Auto-Trunk-12V-A-12V-Volt-80A-Transparent-4Pin-Wire-Relay-Relays-/290642415037?pt=Motors_Car_Truck_Parts_Accessories&vxp=mtr&hash=item43aba34dbd

[poleonpom]

Great, thanks, that makes sense. I've been thinking of wiring up some 12v computer fans to keep the relays temp down.

[wayneg]

I was going to suggest the computer fans but then thought they were 5v or is that just a USB port?

[poleonpom]

Guys,
I've decided to follow all your advice and do a complete component-by-component refurb.
I've ordered a couple of new relays and will then re-solder the fuse box.
I've just fitted new heater O-rings (s/b F-rings with all the words I used to coax the little b'tards into place: 3 times!) and whilst I had the lower dash out I crimped the fan connectors; blowing a gale, ta.
Soldering in new potentiometers into the blend motors, replacing pollen filters and sticking the vac cleaners as far in as pos.
Also looked at computer fans for the fusebox, they are 12v so in they go.

[Hoges]

FWIW: If your fan relays are scorched, it's possible that the fans have been labouring long due to blocked pollen filters. I've had my truck in Bris. for 5 yrs now and having replaced all the relays as a matter of course when I bought it, there's no hint of brown scorching on the fan relays since then... even though the fans are running flat out most of the time. I'm not sure that a 12V computer fan is going to make much difference in the fuse box, other than to draw in dust and engine heat... just a thought

[p38arover]

FWIW: If your fan relays are scorched, it's possible that the fans have been labouring long due to blocked pollen filters.

I've decried this view for years but it seems to have become the accepted view.

When airflow is reduced, electric fans draw less current. There is plenty of information about this on line and in text books.

Eventually, Scotty on the RR.NET took the air con system from a P38A and did some tests. He was expecting to find I was wrong. He found, however, that I was right and that with blocked filters, the current draw was lower. He documented these findings (with photos) in a thread on RR.NET last year.

[benji]

there are 50amp units available at Jaycar too. After replacing the fuse box recently I've externally mounted the to fan relays with 70amp ones. I figured if I take out the heat, the board is going to last longer.

Been looking at a computer fan too and piping the air in from the cabin. I've got a 100x100 fan bolted into a square to 50mm round down pipe piece. But just can't seem to find room under the dash to mount it.

Just for reference, there are a few different numbered fuse boxes. As long as you don't go backwards in years you can run any of them as long as they're for the v8. (obviously bosch is different though). I'm running a june 98 build fuse box in my oct 95 build HSE.

[p38arover]

Been looking at a computer fan too and piping the air in from the cabin. I've got a 100x100 fan bolted into a square to 50mm round down pipe piece. But just can't seem to find room under the dash to mount it.

I remember seeing your post on RR.NET about this.

Regrettably, the search function on the new RR.NET site doesn't seem to be able to find anything any more, hence the reason for not giving a link to the current draw tests done by Scotty. As well, a lot of the pix have disappeared,

[benji]

yes i've had some arguments with the computer screen about the search function too. My wife tells me not to argue with inanimate objects:p.

I'll post some pictures up tommorow.

[benji]

I'm not sure if these pictures will work out, but; here are the photos of the external fan relays.

If you look closely in the fuse box, i've had to cut away the plastic pannel that sits below the relays, and the external relays are simply bolted to a piece of flat that's held in by the corner of the fuse box itself. Therefore, the external relays, and the wiring sit under the battery cover.


42903

42904

42906

[poleonpom]

I'm not sure if these pictures will work out, but; here are the photos of the external fan relays.

That's a much better solution, I think I'll do the same, thanks

[jangona4]

Benji could you email me the how to on the way you modded your fusebox. jangona24@gmail.com I just got a 97 P38 I love the truck but have some issues to fix and one is the fusebox RL7 burnned up. thanks