Electric cooling fan relay

[Flyinghorse]

I was out enjoying the CRS on Sunday when I noted the radiator cooling fan was not coming on when I stopped, and it was a hot day.
   
   On investigation I found the micro relay that operates it had failed.
   What surprised me was that the main fuse /relay board in the passenger footwell has nothing for the radiator cooling fan ,nor in the fuse/relay layout in the chassis book.
   
   I found the relay in the engine bay n/s above  the battery tray.
   My car is modified, so I am interested in where other non modified CRS cooling fan relays are? They may be the same as I don't know if this was modified on my car, or original fitment.
   I have ordered 2 ,with one as a spare to carry. The relay that had failed was not any recognised brand,but was sitting in a ripaults relay carrier 45bRELH and I have ordered 2 durite relays from http://www.gsparkplug.com/shop/
   Durite - Relay Mini Make/Break (A term) 40amp 12volt with Diode Cd1 - 0-727-64
   I have looked at the relays in the main box,and the starter motor one is worth getting,as is the durite 728-12 which is used 4 times.
   The motto is carry a spare relay.
   I also carry a thick copper wire insulated relay jumper just in case.
   Graham
   (n.b on a separate note coil's & ballast resistors can also cause issues so sparing those up is no bad idea. May as well just get a second CRS)

[Flyinghorse]

After a second relay failure I decided to investigate further still. I decided a 40 amp relay on spade terminals for running a fan is a bit lightweight,so recently installed a lug eye 100amp relay and so far it seems to be doing fine.
   The relay can be found here:
   http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=321219479424&ssPageName=ADME:L:OU:US:3160
   
   I am still interested to know what size relays other MkIV,superblower and CRS owners have in their cars and where they are positioned.
   
   Graham

[silty]

The relay is in the passenger footwell on my Lightweight.  No fuses located in the engine compartment at all.
   
   Regards

[Flyinghorse]

Jim,
   Thanks. If its not to much trouble the code number or amperage would be good to know.
   
   I would have thought that there might be 2 big 40-60 amp fuses in engine bay near the battery/coil/ballast resistor.
   
   Regards,
   Graham

[silty]

Graham,
   
   The fan relay in my Lightweight is a Lucas SRB500, rated at 40A I believe.  There are several SRB500s in the footwell fusebox for other functions too.
   
   I confirm there are no fuses in the engine room at all (unless very well concealed).
   
   Cheers

[Paul Mundy]

Graham,
   
   For your information my `98 superblower has two fuses in the engine bay, 20 & 60 amp. Not yet sure what they serve however they are located on the bulkhead above the battery.
   The cooling fan relay appears to be part of a control box arrangement mounted in the front of the engine bay behind the screenwash bottle.
   Apologies for delayed reply , hope it is of assistance.
   
   Regards
   
   Paul

[Flyinghorse]

Paul,
   Many thanks. I also have the 2 large fuses. One is 60 amp and you should find the 60 amp is for the FAN. When that's removed on my car and on another local CRS the fan stops.
   
   Would be interesting to know the rating of the fan relay on a standard car near the water bottle given the fuse is 60 amps. I suspect that's fused for peak start amps. I need to put a clamp on amp meter on to see running amps.
   
   Not sure what the other Maxi blade fuse is for(yet)
   Graham

[Paul Mundy]

Graham,
   
   Following your last post and further investigations, the other 20amp maxi blade fuse appears to be to the charging circuit. When it`s removed my ignition light illuminates.
   I have recently had an issue with my car where an error code indicated that the permanent live to my eec iv pcm was being interupted, it transpired that my car was wired incorrectly when built, the required permanent feed was switched to the ignition.
   During the course of my investigations I examined the control box behind the screenwash bottle, this like the fan on my car appears to be a standard Ford Mustang item, and is actually refered to in the mustang workshop manual as a "constant control relay module". It contains relays serving the fuel pump,pcm,and two for the cooling fan for both high and low outputs.
   I have not dismantled my unit but google images indicate that each of the two cooling fan relays are rated at 40amps.
   
   Regards
   
   Paul

[Flyinghorse]

quote:Originally posted by Paul Mundy
   
Graham,
   
   Following your last post and further investigations, the other 20amp maxi blade fuse appears to be to the charging circuit. When it`s removed my ignition light illuminates.
   I have recently had an issue with my car where an error code indicated that the permanent live to my eec iv pcm was being interupted, it transpired that my car was wired incorrectly when built, the required permanent feed was switched to the ignition.
   During the course of my investigations I examined the control box behind the screenwash bottle, this like the fan on my car appears to be a standard Ford Mustang item, and is actually refered to in the mustang workshop manual as a "constant control relay module". It contains relays serving the fuel pump,pcm,and two for the cooling fan for both high and low outputs.
   I have not dismantled my unit but google images indicate that each of the two cooling fan relays are rated at 40amps.
   
   Regards
   
   Paul
   

   
   Thanks for that information. I don't use my relay box so decided to open it up --this is whats inside:
   
   
   The black Bosch relay is 40 amp,not sure about the 2 grey ones (Omron with Ford part# f7df-14a640aa) and assume they are the fan relays you refer to .
   This relay seems easy enough to obtain from US via ebay etc:
   http://www.ebay.co.uk/itm/FORD-CCRM-RCM-CONSTANT-CONTROL-COOLING-FAN-A-C-AC-RELAY-MODULE-F6SF-12B577-AA-/201125926125?pt=Motors_Car_Truck_Parts_Accessories&fits=Model%3AMustang&hash=item2ed40a14ed
   
   My main observation is that nothing is replaceable without a soldering iron  so having a spare of this relay box might be a good idea given it controls several critical functions.
   
   Graham