The battery in our '93 is flat so I can't test the operation of the P-N switch, but looking at the schematic on page 30 of the Electrical Guide, the Park and Neutral sections of the transmission rotary switch are in the starter circuit, but the "Park Micro Switch" is not - it connects between the CPU and ground. Several other components connect to the CPU as well, such as the Gear Shift Relay and Key Lock Relay and the Ignition Switch, so it would be worth checking your CPU electrical connectors for any signs of corrosion or water ingress, which have been known to cause problems.

Regarding the relay locations, they are shown on pdf page 10 of the Electrical Guide, but if the relays in your car don't match I suppose it is possible that if your car is a late '94 it may have some differences that aren't documented in the manual. Maybe Larry can shed some light on this.

Cheers,

Don

 

Don, that's pretty much the way it is on the '94 - with the exception of a 7th relay to the left of the group on the firewall. (Don't know what that one is for, possibly the block heater or some other component fitted to Canadian models?)

The engine firewall relays were/are all originally the blue Hella's which were replaced with sealed units (stealth recall) on receipt of customer complaints/issues related to relay function.

The firewall relays are all subject to corrosion and failure: that's why they were superseded with the waterproof black relays. Not all fail, but for the cost of sealed units, esp aftermarket ones, it's a good long-term strategy to replace the blue Hella's.

Failure of the A/C clutch relay is often the cause of A/C faults and if the transmission ECU fails it will turn on the trans warning light/put the trans into limp home mode.

The oxygen sensor heater relay failing will cause the fuel pump to quit running and stop the flow of fuel.

If the EMS relay fails, it will shut the car down.

The relay sockets can also be problematic so as a routine maintenance issue I always check they are in good condition.


cheers


Larry

 

Thanks again Don,
I removed and cleaned EMS, and main ground behind the cylinders. I have now been using the Engine Management System Diagnostic Guide to go through all the systems. I have not located The Electrical Guide, although the electrical diagram is with in the engine management system guide. The EMS test good, I have up graded to a good test meter that I can read and hold the voltages so I know that I am getting the correct readings at the ignition amp, coil and EMS. so I feel like the back probing at the fuses and the switches is going back words from that point. I have gone through the P-N switch test procedures and I am to the point on DTC 69 on page 119, (test for voltage under 1 volt in park-and over 4 volts in drive.) I have under 1 volt in park but the voltage does not change from .77 v at all when it is in drive or any other gear for that mater. although the can will not start so the test procedure is a little off.
looking at the Service and repair manual page 167 it shows two groups of three relays on the firewall but my car made in 3/94 has a group of four relays twords the center and three relays out broad. and I still have not found the ignition relay.
I have talked to a lot of jag people in town and everyone is amazed that it will not fire!

I'm still working at it and I i'm learning alot about my Jag, but no love at al.l
Dano

 

Hi, here's another link to the electrical guide for your 94MY car, Don posted it earlier in the thread - perhaps you overlooked it?

http://www.jagrepair.com/images/Auto...ec%20Guide.pdf

Take a look at the pdf, page viii - all the relay locations are shown and clearly labelled - the ign relay isn't in the engine compartment btw.

The "seventh" firewall relay (white base) [in the group of four you mention] is peculiar to the 94MY and isn't shown in the pdf - not sure what that one's for either!!!

Larry

 

I still can't find the Ignition relay. Take a look at some pic's tell me what you think guys and thank for hanging in there with me. I think at this point I need to know for my own sanity.
Dano







Relay groups of three and four, not three and three, But none of than are the right wire combo, i.g. brown, blue/white white/pink, brown/black.




According to the diagram I would assume that the relay would be in the upper left but not there.




I even removed the CpU, large relays, EMC units to look behind them.




I looked behind the carpet and tryed to see if it was behind the console.




I can't find it or any color combo of those four wires anywhere...

 

I've never looked for it but I think it must be under the center console, near the transmission selector?

Good luck!

Larry

 

Hi Dano,


In the Electrical Guide, which I think we've linked to previously, the page before each schematic diagram contains data related to that diagram. Every component, electrical connector, ground and splice is identified, and except for the splices, the location is given. Pdf page 18 states that the Ignition On Relay is mounted behind the radio. I hope you find that to be true on your car.

Removing the radio is fairly easy. Off the top of my head, you unscrew the center console compartment screws and remove the ash tray, then unscrew two nylon wingnuts on the underside of the ski-slope wood veneer trim, remove the gear shift knob (it just unthreads), remove the J-gate trim (just carefully pry it out), carefully remove the ski-slope, then you'll see about six Phillips-head screws that secure the plastic frame that holds the radio and Climate Control Panel. You can probably snap the radio out by itself, but for access it's easier to remove the six screws and carefully work the entire assembly out including the climate controls.


Cheers,


Don

 

Ignition relay is on the right side of the radio inside the center console just above the passenger seat controls. However, I must tell you (because I just had to deal with a ignition failure issue on my 93), is that if your dash lights come on, and the car cranks, your ignition relay is good.