David,
The SII window switch wiring is very different from the SIII, particularly when it comes to the earth (ground) connections. In your colored diagram it appears that there is only one ground for all six switches and it is through pin #4 of the right front switch. Is this correct? If so I recommend a good inspection and cleaning of that ground. The SIII cars have multiple grounds for the window switches.
The other thing I noticed is that there seems to be a difference between the colored diagram and the original scanned black and white diagram that you provided when it comes to the ground. In the colored diagram pin#4 of the RF switch goes directly to ground. In the black and white diagram pin #4 of the RF switch goes to a switch (component #215) and I canât see where the ground is.
My point is that a bad ground, in addition to tarnished switch contacts, can be contributing your left rear window problem. Especially since there seems to be only one ground for all six window switches, which is surprising to me.
Yes, Paul, it is a single ground and I will check it carefully. Thanks.
As to the discrepancy in the diagrams, thatâs a good catch. Switch 215 is the window shutout switch. So in the Jaguar wiring diagram (the BW pic), they show +ve from switch 215 connecting to 3 on the window switch and ground connecting to 4. It looks like either will work but the two diagrams do contradict each other on which connections are +ve and which are -ve. Well spotted. Thanks.
I started working on this today but I had forgotten how little play jaguar left in the wiring to all those power window switches making it hard to manipulate them and how dark it is inside the console when I am trying to see the colours on the wires! Not fun. Iâll try again tomorrow when I have more time.
The idea was that you would put relays, so no problem with load.
If you donât, then yes.
Alternately, you could bring a big fat fused cable from the battery to the center console, split it to Front and Rear windows, install two thermal breakers and connect the switches in parallel. It will improve things with minimal work.
Yes you are correct, sorry for the typo.
I corrected the original post to avoid confusion.
**
The thermal breakers can handle two windows, but likely not more, DavidâŠ
However, the only thing that will happen when overloaded is that the breaker trips and the windows stop. The breaker will then reset, to resume operation - no harm done.
But it is of course very important that the circuit power is fused!
Well I swapped my newly cleaned spare switch for the front left rear window switch and no improvement. However, I noticed both the switch I removed and the cleaned one seem to have less emphatic spring back to âneutralâ position when released than all the others. I am investigating that further and will try swapping a cleaned up rear left rear window (last in the S2 chain so I should be able to remove it from the circuit with no impact on the other switches) next but have ordered an NOS on in case I need it.
I should have done this work in December. May in Florida is not a great time to be in a non-airconditioned garage or outside.
Anyway, I now have given up on a couple of my window switches - my cleaning hasnât improved their performance. So I have tracked down and ordered 4 NOS ones. They look like they may be a later incarnation of DAC1301 than mine but they are right for my car. Maybe they will help. If not, I may go the route of adding relays to at least the rear windows as they are slow to move anyway. The front ones are pretty fast.
Iâll update here again when I have tried the NOS switches. Meanwhile, I had to take the dash apart today as I was putting LED bulbs in the warning lamp cluster and one bulb holder unfastened and fell down inside the dash! Since so much of the dash is off now, I think I will order LEDs for the instrument lighting too.
So, as I write, all four windows and all six switches work following replacement of the front LH rear window switch. Hopefully they stay that way. I am still considering adding relays to the rear windows as they are pretty slow - 5-6 seconds to raise v. 3.5-4 seconds for front. The speed difference doesnât sound much but itâs quite noticeable. If I go the relay route the car should still only allow one window to operate at a time and I was planning 20a relays with a thermal circuit breaker of 25a. Does that sound safe?
David,
Congratulations on getting your electric windows all working again. Hopefully the new switch, and cleaning the other switches and grounds is all the attention that will be needed for a long time.
Sorry, but I canât help with the new relay matter.
Intuitively the values you recite seem to be backwards ?
Breaker should open before the relay reaches capacity?
In the real world, built in tolerances will likely allow safe and good function.
How many amps does the window motor draw?? f
30 or 40 amp Bosch type relays are plentiful and cheap around here. My lump has a rack of them. Fuel pump, starter, ignition, fans, water pump, torque lock outâŠ
Duh! What was I thinking. Thanks for straightening me out. I donât know what the motor draws. I have a multimeter so I may be able to find out and size breaker and relay accordingly.
If operated for a maximum of 5 seconds any standard relay should do fine. I have the normal relays and Aristides had used the smaller ones just as successfully. As Carl said even listed âthe wrong wayâ round the breaker would do - but you have a suitable breaker you could check!
Nice work! If only we always knew from the beginning âŠ
I seem to remember that the most recent thread on a related problem had a similar outcome: one of the âupperâ switches worked fine for its respective window, but failed to pass on power to the ones below. And thatâs how I read your analysis as well.
My car shows markedly different speeds of operation of p/windows as well. Mind you, I never cared to check with a stop watch, but the sound tells the difference - like an electric toothbrush with either full or almost empty battery. Lubing the channels and cleaning the connections whenever Iâm at these switches have been sufficient to just keep them operational.
If you do install relays, why would you want to keep the âone window to operate at a timeâ scheme?
Just complicates things and adds unnecessary possible failures as every switch will be dependent from the one upstream to get power.
The reason Jaguar made it this way is too prevent excessive currents through the switches if one operates more than one window at the time since all power goes through them.
Not a very good design, in my own humble opinion, and luckily they revised it later on the SIIIâŠ
Besides, being able to work more than one window at the time, especially front and rear pairs, is hugely practical.
20A relays will do the job fine.
I donât remember the capacity of the thermal breakers though⊠They definitely must be lower then the fuse and relay rating.
Check the Amperage of on motor when itâs stalled, but use a cable directly from the battery, and you will have the magic number.
Mind you, they must be resettable and not blow-out.
**
The slow motion may be due to higher friction in the window channels, DavidâŠ
As Aristides mention; you could try powering the rear motors directly, bypassing the switches. This will reveal if installing relays will actually helpâŠ
Itâs a sort of feedback effect; slow moving motors due to friction draws higher currents - increasing the load on the wiring/switchesâŠ
I have to admit itâs pure laziness on my part, Aristides. I am finding it really a trial to work on the wiring to those switches. Each one has six separate wires with female spade connectors on the end to plug onto the switch. The wires are short and the colours of the wires are indistinct. So I thought it would be simpler to leave as much of that in place as possible, let the original Jaguar circuitry operate the front windows directly and the relays to the rear windows but get power from a stronger source for the relays to feed to the rear windows. It seemed the âminimum change for maximum improvement to rear window speedâ solution!
Thanks, Frank, I have done that to the rear left and itâs a very definite improvement so I am confident the relays will help. I have ordered them and an auto-resetting thermal breaker.
**
That 'stronger source will still require fusing, David - the obvious solution is to use the the thermal fuse as a source. It resets automatically when overloaded - saving time and work in replacing blown fusesâŠ
About fuses; they are there principally to protect the wiring from overload - not to protect the items fused. They should not be dimensioned to protect relays; a failed item may cause a fuse to blow - but that item has already failedâŠ
