So I took the cluster out to replace the bulbs with LEDs. put it back in, now trip computer, all the gauges, and half the idiot lights don't work. I checked all the fuses I think. The film looks a little rough so I added a ground to the metal bar. What else do these 2 items have in common, did I miss a fuse somewhere?

 

What year model? On an 89 fuse #4 in the main fuse panel is common to both.

Are you sure you grounded the common on the Instrument cluster and not a supply.

 

I checked and even replaced the #4 fuse. It's got power to both sides as well. So odd...half the idiot lights still work so they must be on another circuit?

 

You have to be VERY careful about replacing the two loom multiplugs back into the cluster, this is a hard task at the best of times, and it is very easy to push the copper contacts awry on the cluster and the plug. It sounds to me as though this is your problem. Nothing for it but to remove and cluster and take a look/realign the contacts and try again.
Greg

 

Greg,

Naive question maybe but aren't the LEDs polarity dependent? Have you put them all in the right way round?

Cheers

Paul

 

Good point Paul, I read it that he had changed the instrument illumination lights for LEDs, but not the warning lights. If, as you sagely suggest, he has changed them all, then it could easily be the LEDs are the wrong way round. Thanks
Greg

 

I missed that too, good pickup.

Most LED replacement bulbs are polarity sensitive.

 

I replaced ALL of the bulbs with LEDs. Could a polarity reversed on one or more of them impact the speedo and trip computer?

 

No. The polarity reversal might account for some of the bulbs not working; but the multiplug (and/or a broken copper track on the bendy blue circuit board) is more likely to account for the speedo problem, assuming it was working before.

 

Here is an rear image of the polarity of the electric circuitry. DAC7999. Up to vin 188104. In 1993.5, the circuity pattern changed. I used this to convert my binnacle lights to LED. Yes, there are some LED that are in polarity. I have posted this message on the forum earlier this year..

 

Very cool image but this is of the newer style cluster. I think this is the image that I need to follow. But it doesn't show the polarity. I'm starting to suspect I have broken one or more of the copper "channels" Can this film be repaired? Anyone know who I would contact for such a service?

http://www.jag-lovers.org/snapsdata/2~1120870845.JPG

 

+1. LED polarity issues aside, that alone can't explain the sudden demise of gauges etc. Whether track damage on film or the far too common multi-plug "oops" issue, it all comes back out to check and double-check.

Greg W, good luck with your film. Repairing foil damage on pcb is one thing, using pens available to "re-write" tracks in liquid silver or copper, but foil tracks on film are rarely treated with the respect they deserve. Many will crack tracks with anything more than modest flexing. Spending 25yrs in a harsh car environment makes them sleeping dogs that can bite hard!

Sorry if I sound so negative but my skin still crawls at the hours spent tracing around with DMM or 'scope probes trying to find "cracks in tracks". On the bright side, it is a task ideally made for DIY. Imagine handing a customer a bill for $1100 once a single minute crack had finally been found and repaired. Let's hope it is the multi-plug issue highlighted by Greg in F.

Best wishes,

Ken

 

The copper track can be repaired OK. Post again if you need to do it. I have no idea what year or model your car is, please add it to your signature; but here is a diagram of what multiplug does what from a 1983 V12 coupe USA model.

 

I have never used conductive pen, so can not comment on its longevity.

I have always repaired traces by soldering wire to the trace (except for surface mount PCB repair)

Greg one problem with the signature is it does not show when you post on a mobile device. Hopefully the developers will fix this eventually.

 

Thanks all. My car is an '89 convertible.

 

Please put it on your signature, so it will appear automatically, or ensure you restate it on every post.

 

The image I provided, of the DAC7999 circuit diagram shows polarity and indicates what color light goes where. This circuit sheet fits Jaguars
XJS from (V)179737 to (V)226645. When I replaced my binnacle lighting, I had to purchase a new DAC7999 due to the shredding to several copper strips on the 2 connections. My LEDS were purchased via Superbright (St Louis).

Mert

 

Back to your problem.

I suspect you have 2 issues. 1) being polarity of LED's and 2) an issue with the cluster traces, more than likely where the connector seats.

1) to ensure all LED's are in the correct way use a 9V battery to check polarity. LED's will only work one way.

2) the connector - use a pencil eraser to clean the connector terminals, and inspect them for damage, most likely they will peal off the backing.

 

So with the gauge cluster out. Everything associated with that fuse is dead (backup lights and trip computer). Is that right. I've checked and rechecked the fuse but how could the gauge cluster cause the backup lights to now not work if the cluster is not even in the car right now?

 

Is there 12 volts at the TC lights? if so swap the LED polarity.

One thing I did forget to mention, DO NOT replace the ALT bulb with LED this will prevent the ALT light from working correctly. This light MUST be polarity independent, otherwise the light will not light if you have failure.

The ALT light is designed to turn on if either the battery or alternator fail. If you replace it with LED the light will light if the ALT fails but not if the battery fails.