Craig,
I can’t comment on the suitability of this relay, but it seems to me that changing the resistance of the W1/W2 coil from 16 to 76 ohms is only going to reduce the current from 0.75 to 0.16 amps. It hardly seems enough to make any difference to an overheating ignition switch…
-David
David,
I came to that understanding as an epiphany a short time ago while fresh out of bed! Though I don’t understand why there is a difference between a continuous use relay and an intermittent relay as used by horn for example?
Best I can see, this relay in question is a 22RA not a 6RA. Does that make a difference?
Hi !
Well the 22RA (SRB301) is the starter relay that connects C1 to C2 & C4 when active whereas the 6RA (SRB111) is a changeover relay that connects C2 to C3 when idle and C2 to C1 when active. But I think the later is also designed for 20A .
Oh sorry - then most of the above is wrong and I just verified that my starter relay also measures only 17 Ohms on the coil.
-Tom
Tom,
The terms 6RA and 22RA denote different families of relays, each of which has many members. The descriptions you have listed apply to one member of each family, but there are other members which have different terminal configurations and connection patterns. This past thread has more details:
-David
What’s confusing the issue, and me, is the original relay I’m trying to replace is a Lucas 6RA relay with the number 33232H on it. It has three terminals W1 C2 & C1 and apparently is no longer available. Somewhere, I think it may have been a post by John Holmes, I saw a resistance value for that relay as 75 ohms prox…
I have located a 6RA with a spec of 75 ohms and plan to add a jump wire between W2 & C2 because my understanding is that the 33232 relay jumps W2 & C2 internally. Any thoughts on that greatly appreciated.
(downloaded the relay document but don’t see the elusive 33232 relay referenced?)
EDITED: Added to
This is what I’m dealing with:
Craig,
I’m confused. If the fans don’t run with the A/C on (cool engine), but do run with the engine hot, then Fan Relay #1 from your diagram is working. The relay that is not working is Fan Relay #2 which has 4 terminals W1, W2, C1, C2 - assuming you really have 12v on the W2 terminal with WU wire. You also show in your diagram that there is 12v on the BG wire on C1 of Fan Relay #1 when the fans aren’t running. If this is the case, I would suspect that the problem may be that the 12v cannot drive enough current to drive the fans because of a high resistance connection somewhere. The first place I’d look for that would be the contacts of Fan Relay #2. If you open up the can and clean the contacts you may be back in business. Then again, I may be completely misunderstanding your desription/diagram…
-David
David!
If it is true that there is high resistance through Fan Relay #2, would that account for the heat build up in the ignition switch? Note that I have since changed the wiring to pull off of fuse 4 on a lug next to the hazard lights to get the fans off the ignition switch and since the hazards are all LED’s anyway I figure the #4 35 amp fuse is, in effect, the same protection as on the other side.
I’m afraid not. A high resistance path will reduce the current, and so reduce the current through the switch. However, if the ignition switch itself has poor/high resistance connections it will get warm. This has happened to several on the forum, and a cleaning of the switch contacts has returned it to normal operation. Sometimes, the rivets that attach the terminals to the switch become loose, and result in high resistance which will cause it to get warm. It’s worth taking a look. I don’t see it accounting for your A/C problem though.
VICTORY!!
Before:
I consider it a great privilege to have all of your assistance.
Craig
I am away to August 25th only with phone so I cant edit photo to show you the areas until I am back and on a computer
Dennis
This may or may not be helpful. My 1971 Series 3 FHC has its original A/C system - with replaced/upgraded components of course. It blows very cold! My very experienced Jaguar tech wired the A/C fan directly to the battery, bypassing the ignition switch, because, he said, of the high current draw. It’s a bit of an inconvenience to keep turning it on and off, but it works quite well. My car has the green ceramic resistor mounted “up in the air” under the bonnet as it get right hot and needs cooling space. The radiator A/C auxiliary fan comes on and stays when the A/C is turned on. Hope yours gets sorted out with the relay.
Hi Ferman,
Noted your post regarding how your tech rewired the A/C fan directly to the battery, bypassing the ignition switch.
I’m writing a book on S3 E-types and this MOD is perfect for inclusion (making them more reliable!!!). Do you have any wiring diagram(s) or such detailing what your tech did? Photo’s would be most helpful too.
Thanks for your assistance and post.
Happy Trails,
Dick Wells
Hey there, Dick. That bit of rewiring was a good move initially, although it eventually bugged me that that noisy fan was always on whether the compressor was or not, so I changed it back. I did change out the thermo-switch to an adjustable one, which worked well. Unfortunately, I do not have any wiring diagrams and since I’ve sold the Cat, no photos. Wish I could be more helpful. I’d be interested in your book when available.
Ferman
704-236-5200 Mobile
704-374-1120 Home
So first question is, what fan are you talking about? The engine fan or the AC blower?
If the AC is on, the blower should be on regardless of whether the compressor is engaged, to prevent air stagnation and evaporator freezing. The resistor only engages on low blower speed, and it does indeed get quite warm. The better way to do this is to use a dual wound motor, but this is not in the Lucas lexicon.
If the otter switch is working, wiring the engine fans always on, or adding a manual switch is pointless. The mod I prefer for S3 is to use the two speed VW fan, with the low speed controlled by the otter. The high speed can be controlled by a manual switch to provide extra air in an emergency.
Wiring direct to the battery post is fraught with problems. First being how to fuse the circuit. The use of undocumented inline fuses in the engine compartment is sure to confuse someone, and not using one promotes smoke release. Better to wire from the unswitched bus in the fuse compartment, adding an inline fuse, which is where you go to check fuses.
