I have a 1983 Jaguar XJ6 (series 3) with AC issues. I know “shocker” lol. Anyways NONE of my blowers will kick on when I switch the fans on with the dash knob. The clutch/compressor does engage and gives me no obvious reasons for issues their. As far as I know anyways. I have read the amps can be issues but not sure if that is my issue and or how to diagnose that problem.Any help on getting my car to blow any kind of air would be greatly appreciated!!
P.S. can some one please explain what I have here in the photos?? I know this is not the amp, but it has the same plug on top as the amp. Thanks!!!
The OEM A/C amplifiers (C45402) have a high failure rate. If you search the Jag-Lovers archives for “A/C amplifier” you will find dozens (hundreds?) of posts about problems that others have had, and what some have done to fix them. The good news is that a prior owner or their shop installed an aftermarket A/C amplifier, often referred to as the “shotgun shell A/C amplifier”, in your car. This was most likely because the OEM A/C amplifier failed as they often do. The shotgun shell aftermarket units seem to be very reliable. I installed one in each of my Series III XJ6s before I sold them when I got their climate control system heat and air conditioning working properly. Both of their OEM A/C amplifiers had failed.
The first place that you should check for inoperative heater blower motors is the 50A fuse located in the Auxiliary Fuse Box under the passenger side dash (assuming a Left Hand Drive car). Fuse locations are described in your owner’s manuals and also on the decal on the fuse box access panels.
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With no blowers in any switch position, Nikolas - the first step is to check the 50A fan fuse( #6 or# 13, depending on market). If the fuse is intact; a not uncommon fault is a failed fuse holder - due to the high current, a bad connection may overheat and disconnect the wires…
The AC amplifier plays no part in fan operation - it only moves the servo. The 50A fuse provides power to a bank of relays; the switch operates the relays - end power is delivered through a resistor unit, which gives different fan speeds…
Checked fuses and all are good. I will check fuse holder status this afternoon after work. While checking fuses and playing with the temp knob i did see the servos responding to any temp i set the nob to so good news their. Where would i find this bank of relays you described? This car has a long running trend of the issues being bad relays. (I have already replaced 4 in other systems that ended up solving problems) I have a sneaking suspicion my issue lies in the relays since my fan knob on dash has no problem activating my compressor but will not turn on a single blower motor?
Hi Nik, did you run the car up to temperature for testing, and do the fans work in defrost? Also good practice to try a new fuse, they can look great and still not work. And check for power at the fuse if you didn’t.
You’re lucky; your amplifier seems to work and the relays are on the opposite side of the servo, so left of the transmission tunnel, it’s the thing with the always live (brown) connector in the centre.
David
I have replaced every fuse in the main boxes and in lines as i come across them with the correct conversions the agc bussman fuses. After replacing the second relay in the fuel injection system I decided this was a 20 min job that would save me alot of time and issue later on. So hopefully fuses are good though out of paranoia ill recheck my 50 amp fuse.
It was up to temp as well.
Also no defroster fans ethier. Its like my ac system does everything right, but blow air lol! I think i saw the relay the last time i was messing with it, so ill go through clean every connector and prong and go from their. If that doesn’t work i might replace that relay out right just eliminate any chance of it being the culprate
Nikolas,
The A/C Relay (C46179), actually four relays inside one plastic covered box, is located just behind the cheek panel near the drivers right knee assuming a Left Hand Drive car. Attached is a picture of the Relay that was in my 1987 XJ6 parts car, circled in red, before I removed it. There are about a dozen wires connected to it, so if you decide to remove it first disconnect the battery and take lots of pictures and notes as you remove the wires so that you can put the wires back on correctly. The four relays inside the Relay control the various speeds of the blower motors.
I have removed this relay from my XJ6s before when I had blower motor issues, tested them, and discovered on occassion that one or more of the four relays inside had failed. So that could possibly be your problem. I have also had failures with some of the four microswitches located behind the Mode Control Switch and had to remove and replace them to get the blower motor fan speeds to work correctly. There are easily accessed connectors on the wires going to each of the blower motors, located beneath the carpeting under the right (passenger) side cheek panel. I have disconnected those connectors and applied 12V power to each blower motor independently to test and positively identify a failed blower motor.
Start simple…the rabbit hole that is the climate control system can get deep.
First please understand that there is a difference between British Lucas fuse ratings and North American Buss fuse amp rating standards…essentially, when replacing a Lucas fuse with a US fuse…use 50% of the rating. A 50 amp is replaced with a US 25 amp. Over fusing can heat and distort the fuse holder.
Since you claim the servo is responding to temp knob changes…i recommend you first check for 12 volts at the large brown with white trace wire at the main fan relay pack on the left side of trans tunnel. If you have 12 volts…you either have failed relay, failed fans, failed resistor pack (unlikely) or bad grounds. No voltage…recheck fuse and holder.
You can bridge from the large brown power wire to any of the solid color wires Red, Yellow, Blue or Green slate to bypass the relay contacts and power the fans directly. If they run…I would start with the relay pack.
Of course, the various fan circuits also switch grounds to over ride various speeds. But in all cases…you should have at least LOW fan speed.
The shotgun shell style amplifier is a solid state unit which works fine as long as the servo is in good working condition…as our cars age…the grease in the servo gear box become thick and tar like causing amp draw to increase beyond the max rating of 1.5 amps for the IC chip…generally causing them to crack and destroying the amp.
So with all yall’s help I believe I have a bad relay. Going to replace and retry. but other issue reared their head during my AC relay testing. Car was idling great then just quit like I had turned off with the key. It then took more than wanted turn overs to get it to idle again. It idled great again for 10 min, then died in the same manner. So I probably will have to track down that issue then return to the AC after ordering a new relay.
In your photo of the relay their is another part I’m intrested in getting a replacement for in my car. The gold “squarish” part at the top left of the relay. That left relay fasening bolt actually holds this part in place as well. On my car it has two small hoses coming off of it as well as two electric plugs that resemble the electrical plugs on the ac relay.
Sorry for the poor description just not sure what this part is or is called. Mine is ceroded and rusted in my vehicle so knowing at least its name would greatly help me find a replacment!
The part you describe is a vacuum switch for the recirculation flaps.
It is powered by a double pink wire…energized in two conditions to allow vacuum to close the flaps…ignition on with climate control system off and also in full cooling.
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As Paul says, Nikolas; there are 4 relays in the relay bank - the can’t all fail…
While the fuse/fuse panel checked out OK; at the relay bank check for power on the brown/white, as Gary suggest with a test lamp(!) - verifying power to the relay bank. A voltage check, with a meter, is not conclusive…
If powered; disconnect brown/with - and connect it directly to the relay connectors in, turn, for red, yellow, blue and green/slate (whichever is easily accessible). This bypasses the relays - powering the fans directly.
If this/any runs the fans - the relay bank is not the main problem; a failed relay will usually only kill one fan speed.
Another access point for testing is the fan resistor unit; the wires mentioned connect the relays to green/slat which connects directly to the fan motors.
There is no point in changing parts that are functioning…
Nikolas,
As Gary mentioned, that is the Solenoid Vacuum Valve, RTC670, that controls the vent flaps.
If you are going to work on this car yourself you should be equipped with the proper technical data. You should have the Jaguar Series III XJ6 Parts Catalogue RTC9885CF, the Jaguar Series III Service Manual, the Jaguar S57 Electrical Guide, the two Owners Manuals (green Series III Handbook and the white XJ6 Series III Maintenance Handbook) to help you navigate the complexites of components, systems, operations, servicing, and repair of these vehicles. I was fortunate to get both owners manuals with my XJ6s and I purchased hard copies of the other documents on eBay. There are two other documents that are available to download for free on Jag-Lovers that would be helpful for you, “JAGCARE III” by Dr. Gregory Andrachuk, and “Experience in Book” by Kirby Palm. You can find them by using the Jag-Lovers archive search function.
Nikolas,
I recommend that you start a new thread for your engine problem and use a new subject line any time you start a new subject otherwise things will get confusing real quickly.
Gotcha thanks will do. Sorry for any confusion just a 23 year old kid trying to figure this car out and have it running as a surprise gift for my grandfather in law. Was his old car and also the car my in-laws love story started with. So I deffiently appreciate every bit of advice you can give in helping me get the old girl humming along again.
Nikolas,
Thank you for the back story on your car. I am sure that I speak for everyone on this list that we will help you sort out the family XJ6 owned by your grandfather-in-law car. Collectively this list represents decades ( hundreds?) of years of experience working on every system in these cars and the Jag-Lovers archives have detailed information to help you with any possible questions or issues that you mighr encounter.
I look forward to helping you at every opportunity.
Paul is speaking for everyone I have come to know closer on this list, for sure. And to make things even better: other forums may have hundreds of years of collective experience as well, but we have them in a single-digit number of users! And I certainly don’t count myself in …
Anyway, it sounds like the car has always been kept in the family. It is always great to begin with a car with known history as it makes troubleshooting so much easier.
Yet, starting with a restoration of most any 1983 car should give you bigger issues to fix than the blower fuses and an engine thing. What’s your agenda and how do you think to tackle it? Most importantly: when is his birthday?
