I am having problems with the Teeves III ABS in my wife’s 1990 XJ-S convertible. The red BRAKE warning light was taking longer and longer to go out over time after starting up the car and is now on continuously. I suspect that the Combined Pressure Switch (JLM1465) has failed because the ABS pump seems to work properly, the amber ANTI-LOCK light comes on and goes off proprely when starting the car and the ABS appears to work properly when I slam on the brakes on dirt roads.
I started some detailed troubleshooting of the ABS and have some initial questions regarding components and wiring that I hope someone can help me with.
What is the Jagar part number of the Brake Warning Inverter Relay in the attached picture?
The relay is shown in my S-57 Electrical Guide but not in my XJ-S Parts Catalogue.
What is the correct wiring to the pins on the Brake Fluid Reservoir connector? My S-57 shows pin #1 WG, 2 PG, 3 B, 4 BY. However, the attached picture of the numbering on the plastic connector shows that pin #1 was not used, 2 BY, 3 B, 4 PG and 5 WG. Is my connector wired incorrectly or is the S57 in error?
I am reading through the Repair Operations Manual now as well as looking through the Jag-Lovers archives on ABS issues so I will probably have more questions about the Combined Pressure Switch and the way the fluid level sensors in the reservoir work since it looks like they could cause the red BRAKE light to come on. BTW, I followed the procedure for making sure the reservoir fluid level is at (perhaps even slightly above) the correct MAX.
Paul
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
2
This is in my Book somewhere. The Combined Pressure Switch is closed when it should be open and open when it should be closed, so a relay was installed in the circuit that reverses its function. Later, somebody got wise and introduced a new Combined Pressure Switch that is open when it should be and closed when it should be. Then the earlier, stupidly designed Combined Pressure Switch went out of production. So, to replace the early design switch, you will only find the later type available. To use it, just install it and remove that relay that reverses its function and connect the wires up directly.
The new style switch is a different color than the original. Otherwise it looks the same.
1 Like
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
3
IIRC, one way to vastly improve the reliability of your Jaguar is to throw all the Hella relays in the trash and replace them with Bosch relays. I suspect someone here can confirm that. I think it may actually have been a TSB.
Kirby,
Thank you for this helpful information. I took a quick look through the
ABS section of your book yesterday but didn’t see this info there. I will
take another look now that I have these insights.
All,
I spent more time working on the car today with the S-57 Electrical
Guide and multi-meter. I believe that I confirmed that the failed
component is the Combined Pressure Switch, JLM1465. When I tested the pins
on the switch in the depressurized state I had continuity only between pin
1 (B) and pin 4 (WP) which was correct. But when I checked for continuity
after pressurizing the system there was continuity between pin 3 (PG) and
pin 5 (WU) as there should be but not between pin 1 (B) and pin 2 (BLG)
indicating that one of the pressure switches did not close as it should.
The continuity between pin 1 (B) and pin 4 (WP) was lost as it should be
with the system pressurized so that pressure switch also appears to be
working correctly. I guess that 2 out of 3 ain’t bad.
I am investigating my options to remove and replace the Combined
Pressure Switch in order to get the ABS system, particularly the red BRAKE
light, to work properly again as it is always on now.
As a side note during my testing today I believe that I discovered
another error in the ABS figure 28.1 of the XJ-S 1990/1991 MY S-57
Electrical Guide. Two of the pin numbers on the Brake Warning Inverter
Relay are swapped. The BY wire goes to pin 30 and not pin 85 as shown and
the BLG wire goes to pin 85 and not pin 30 as shown. I did some head
scratching over this, then traced the wires and finally removed the cover
of the relay and tested it manually to conclude that the pin numbers as
shown were in error. I no longer suspect this relay as a problem because I
tested it, found the error in the Electrical Guide and also found the
problem in one of three pressure switches inside the Combined Pressure
Switch.
I made additional progress today by calling the local dealership and reviewing the Jag-Lovers archives. The correct part number for the Combined Pressure Switch in my wife’s 1990 XJ-S convertible (VIN 175XXX) is JLM1908 and not JLM1465 as I originally thought. The JLM1465 was used up to VIN165790 and the JLM1908 was used from VIN 165791 and forward. As expected the dealership doesn’t carry either one. The parts guy was also unable to find any reference to the Brake Warning Light Inverter Relay or provide a part number for it. I no longer suspect that part is bad but thought I should pass that info on in case anyone is looking for one.
I found several posts in the archives, some by George Balthrop, that were very helpful in understanding how the Combined Pressure Switch operates and the results of internal switch failures. I appear to have a failure of the switch between pins 1 and 2 that is no longer closing as it should when the system is pressurized. I am looking into options to get a used one, or possibly to a new GM part (2553-3700?) that is supposed to work but may require some connector or wiring modifications.
I fixed the problem with the red BRAKE light beong on constantly in my
wife’s ABS equipped1990 XJ-S convertible today. When that BRAKE light
started to stay on longer and longer after start, I initially suspected a
problem with the brake reservoir level switches, but I was wrong. They
tested fine. When the light stayed on permanently it was time to fix the
problem. It turned out to be a failure of the JLM1908 Combined Pressure
Switch which also turns on the red BRAKE light. I purchased a used
replacement switch on eBay, removed the old failed JLM1908 and replaced it
today with the used replacement one.
I depressurized the 2,000 psi ABS system for obvious reasons before
removing and replacing the Combined Pressure Switch. When I started up the
car with the replacement switch and a depressurized ABS system both the red
BRAKE light and the amber ANTI-LOCK light illuminated, as they should, and
they both extinguished after about 10 seconds. For the past few months the
red BRAKE light would not go out so the car has been in my garage for most
of the time while I tried to figure this problem out.
I am particularly thankful for all the posts that I found in the
Jag-Lovers archives that helped me figure out how to troubleshoot this
problem down to the failed component. I simply would not be able to keep
this car on the road myself without Ja-Lovers.
BTW one complicating factor was Jaguar’ use of two different
configurations of this ABS Combined Pressure Switch, first the JLM1465 and
then later the JLM1908, that both have three pressure switches inside but
work differently and are wired differejtly. Once I figured out which one I
had (JLM1908) and which of the three internal pressure switches had failed,
all I needed to do was find a suitable replacement at a reasonable price
and swap it in for my failed one. I found a replacement on eBay for about
$80 (ouch!) my favorite shopping place for used parts for my six Jaguars.
New JLM1908S were also listed on eBay for $600 or $1,000 but my pockets are
not that deep so I opted for a used one.
Paul M. Novak
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
7
How can those switches be that expensive? This is not a unique Jaguar part, the same ABS system is used on GM products.
Buick Reatta’s seem to have some followers and are probably the largest existing market for the Teves III. I got a new accumulator (and by new, I mean NEW – production date 2016) from one of their preferred vendors.
But, the prices are ridiculous. The ABS assembly is over $3K. Pumps and switches are pushing a grand. Must be a supply-demand issue
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
9
Again, my recommendation would be to gut that system anyway. It’s unsafe, as a single failure on a front brake line can leave you with no brakes and feeling around for the handbrake. I recommend tossing everything Teves III in the dumpster out back and either upgrading to Teves IV or simply reverting to non-ABS, vacuum-boosted brakes. Either system is safer than the Teves III IMHO, and there’s simply no doubt that they’re cheaper to maintain.
Kirby,
As suggested the price of these ABS Combined Pressure Switches is probably a supply and demand matter. The Jaguar dealerships don’t carry them any more. If you search eBay the used ones are about $70 plus shipping, and new OEM units are available for $624.80 or more than $1,000. Once I found a used one at a reasonable price I got it and the car is working properly and back on the road again.
All
As a closing post to this string I am attaching two pictures of what I believe are the two configurations of the ABS Combined Pressure Switch used in the XJ-S. After my investigation over the past 2 months I believe that the switch on the left with a black connector is the earlier JLM1465 and the switch on the right with the blue connector is the later JLM1908. They each have three internal pressure switches that turn the pump on/off, turn the amber ANTI-LOCK warning light on/off, and turn the red BRAKE Warning light on/off, but they work differently and are wired differently at the connector and in the car. So they are not interchangeable unless you plan to make changes to how your ABS system is wired in your car.
For a variety of reasons I prefer to keep my 6 Jaguars original and for the most part will continue to repair and return them to their original design as long as I can. In this case a used JLM 1908 was reasonably available and once I figured out that I needed a replacement one, it fixed the problem.
I hope that this string helps others who might notice their red BRAKE light staying on longer and longer when they start up their XJ-S/XJS, and then one day it doesn’t go out despite having a proper level of DOT 4 brake fluid in the reservoir. If that happens, it might be an internal failure of the Combined Pressure Switch and time to get a replacement one like I did.
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
11
Thanks for the photos! As I understand it, the earlier switches worked the wrong way and required a relay in the wiring to reverse their action – close when the switch went open, etc. Later they realized their mistake and introduced the blue switch and eliminated the relay. The earlier switch was discontinued, so anyone with a switch failure had to install the blue relay and remove and bypass the relay in the wiring.
But you apparently have a later car that came with the blue switch to begin with, so no such fiddling is required. When you first mentioned the price for the switch, I presumed you were mistakenly looking for the early version – being discontinued, they’d understandably be difficult to find. I still can’t believe the later switch is so expensive.
Kirby,
When I looked through the archives I came up with the same opinion about the Combined Pressure Switches and Brake Warning Light Inverter Relay, but what I found was exactly the opposite. I believe that the initial design did not use the Brake Warning Light Inverter Relay and it was installed in the later cars when an updated Combined Pressure Switch was installed.
Jaguar introduced the Teves III Anti-Lock Brake (ABS) system in the XJ-S in the 1989 model year. When I reviewed the 1989 XJ-S S-57 Electrical Guide it showed a Combined Pressure Switch but no Brake Warning Light Inverter Relay. Per the Jaguar Dealership parts department that switch was JLM1465 and it was used until VIN#165790. I obtained one of these JLM1465s along with its connector and wires from a 1989 XJ-S VIN #149XXX, discovered it had a black connector unlike my blue one, was wired differently at the connector and one of the three internal switches tested differently than I expected in the unpressurized state. I returned that switch to the seller and received a refund.
My wife’s 1990 XJ-S convertible, VIN#175XXX, had the blue Combined Pressure Switch JLM1908, and it also had the Brake Warning Light Inverter Relay. This matched what my MY 1990-1991 S-57 Electrical Guide showed as the correct configuration. I purchased the used blue JLM1908 on eBay, installed it and it fixed the problem with the red BRAKE light staying on after start. Now that light and the amber ANTI-LOCK warning light both illuminate after cold start and then go out after about 10 seconds showing that the system is properly pressurized.
As a side note you will note in the previous picture that I posted that the black JLM1465 has a much smaller diameter (30 mm?) than the blue JLM1908 (40mm?). I didn’t have any combination wrenches that large and used a pair of large vice grips to remove the failed JLM1908 from the car. From the marks on the used one that I got on eBay and installed I suspect that is what the seller did when they removed it.
Paul
1 Like
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
13
Can you tell us what size hex that blue switch is?
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
14
If I ever get around to updating the Book, I’ll have to correct that.
Kirby,
I think it would be helpful to have other prefacelift XJ-S owners with
properly working ABS chime in. What I discovered worked for me, but it
appeared to contradict what others stated in the archives. I was surprised
by what I found out.
For instance the following might be helpful:
Do the ABS equipped cars VIN 165790 and earlier have the black Combined
Pressure Switch (JLM1465) and black connector and no Warning Light Inverter
Relay?
Do the ABS cars VIN 165791 and later have the blue Combined Pressure
Switch (JLM1908), blue connector and the Warning Light Inverter Relay?
Kirby,
I measured the blue JLM1908 with a digital caliper and it was about
40.16mm. I tried a 1 1/2" wrench and it was too small and a 1 5/8" was too
large. I guess it could have been 41mm or possibly 1 9/16" but those are
odd ball sizes that I don’t have and didn’t want to buy. So I lost my
patience, got my large vice grips out, and they did the trick. Maybe not
the right tool for the right job that time, but it worked.
Why any reasonable person would decide to use such an unusual size is
beyond me. Who would have those tools?
Paul
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
17
I’m just wondering if there’s something obvious we’re missing, like this is a standard socket size for an oil pressure sender or some other doodad. That’s pretty big, though. Anybody have any ideas?
Ptipon
(Ptipon, Sonora, CA, USA, 1990 XJS, Conv.)
18
Hi Guys,
I have a 40mm, open end and box end. Perfect fit. I have used it to
do this job months ago. Just don’t know if the replacement switch
works or not. I am still waiting for another part on the engine
before I will be able to road test.
Ptipon,
Thank you for confirming that a 40mm wrench is the right tool to remove
the blue JLM1908 Combined Pressure Switch. I didn’t have one that large so
I looked around our town at Sears, two tractor supply stores and three
autoparts stores. No one had a 40 or 41mm wrench in stock. The local NAPA
auto parts store said that they could special order one at about $90 plus
shipping. That is when I decided to try my large vice grips instead since
my old switch was bad and it really didn’t matter if I damaged it on
removal.
I just purchased a 40mm combination wrench on eBay for $15.78 with
shipping included. I may never need to use it, but at that price I will at
least have the correct tool on hand if I do.
I am in a competition with my younger brother over tools, he who dies
with the most tools wins. At this point I am pretty sure I am ahead of him
so it was worth it to get this new tool to stay ahead.
