Hello all,
I’m restoring my 1970 2+2 and working on the wiring. My car does have A/C. On the front cross member there are 2 relays. I know that one is for the radiator fans but I’m confused about the other one that is just below on the same bracket. They have wires going from one to the other. I was thinking it might be the A/C over ride but I thought that was on of the three that are located next to my battery. One of the three I know is for the horn the second is for the alternator and the third I thought was for the A/C over ride. The wiring diagram shows only one relay for the radiator fans.
Could anyone help with the confusion please.
You have 2 A/C relays. If you have the correct wiring diagram, you will see that there is one relay labelled as FAN RELAY 2 which turns on the cooling fan when the A/C is on. It is located adjacent to FAN RELAY 1 on the picture frame. The second relay powers the A/C itself when the ignition is on, and is located with the horn relay and alternator relay on the L/H splash guard.
To clarify, the second relay keeps the fans powered on, defeating the otter switch, whenever the A/C is engaged. It does this by bypassing the primary fan relay.
I truly can’t thank you enough for the great help.
You have explained things so even I can understand this.
This is may first car restoration and you are such a great resource.
I had been using the wiring manual that I had purchased.
After these posts I realized that I must be overlooking other diagrams.
Went to the official Jag manual went through page by page and in the back there were other diagrams that were much more complete including air conditioning.
I installed a new Relay #1 on my friends XKE S2 yesterday. I do not have the “WU” wire plugged in / hooked up yet. I followed the above wiring diagram to connect the wiring to the relays.
Now when I turn on the key, the fans turn on immediately.
Did I hook up the wiring in error, or is this due to not having the WU wire connected?
No. If the A/C blower switch is in any of the “on” positions, then relay 2 will be energized and the fan will be on. But then, you say the WU isn’t connected. So that could mean that the C1/C2 terminals are somehow shorted and the relay is defective. Or the problem may be with the other relay or the otter switch.
We determined the brand new relay (#1) is defective or wired up in error. This came from one of the usuals and is not the metal canister that I was hoping, it is a plastic small cube. Need to find Relay #1, and old canister version that works.
Thanks,
Bob
Can you please help me cross reference with the original wiring diagram and metal canister relay with C1, C2, W1?
New plastic relay:
30 =
85 =
86 =
87 =
87a =
It’s unusual for a Bosch style relay to be bad out of the box. Are you sure you are wiring it correctly? (85,86=W1,W2) (30,87=C1,C2) 87a=C3 Typical mapping.
Since your relay 1 has no W2, you will add a power feed to W2. this can be done by jumpering W2 to C2, using a piggyback connector and a bit of wire with two female disconnects.
This is a change-over relay, unlike the original. That is, whether or not the relay is activated, the #30 terminal is always connected to one output - the #87 or #87A. When the relay is inactive, #30 is connected to #87A. When the relay is active, #30 is connected to #87. If you have connected the relay incorrectly (e.g. using the #87A rather than the #87 terminal), you might see the symptoms you describe.
I have a series 2 E Type US spec with AC. After some recent work on the power steering, I find that the cooling fans do not operate. They do operate when the A/C is on, however. I have tried shorting across the Otter switch , ignition on, to no effect. The mystery for me is that I can only find one relay on the picture frame, whereas from your post, there should be two side by side. Can anyone shed light on this for me? Any help much appreciated. Ross.
You should have two relays on the picture frame. They are very close together, so if you see the one and not the other someone has made some alterations to your car.
Ross, the two relays on the picture frame (AC cars) are not side-by-side. They are one above the other, on a bracket. Look underneath the one you can see.
Here’s a picture of mine, showing the upper relay (original) and a black cube bosch relay with the red wires that replaced the original lower one. Both are attached to the original bracket that is bolted to the picture frame.
I agree, there’s probably another relay down out of sight. I guess it’s possible to wire this with one relay, but it would put an enormous load on A/C switch. Not recommended:
Thank you to John, Liam & Michael! Yes, now I look more closely, there is indeed another relay located directly underneath the one I saw easily. Now to find out why the fans do not switch on…I have the wiring diagram , so I will check the connections. Cheers everyone. Ross.
