More Heating Issues - Troubleshooting the Jaguar XJ40 (Part 1)

[@maxlindstrom5435]

There is a Transistor 2N3055 that is blown when you have only Hi speed on the Fans. the module is inside the Fan enclosure and on the right side it's easy to take the whole package out. I have changed that module with the transistor, on a XJ40 -94 some years ago. It might be the relay also that is blown, it's also placed inside the compartment.

[@johnmoruzzi7236]

So the transistor switches to the resistor bank ?

[@maxlindstrom5435]

@@johnmoruzzi7236 Yes!

[@maxlindstrom5435]

Just a standard 2N3055 or similar spec transistor . Try to clean off the transistor an try to read the P/N. These are common transistors. I replaced one on my -94 Jaguar XJ40 heater blower fan transistor. Similar circuit for variable fan speed. Full speed bypasses this curcuit so I had full speed fan but not variable.

[@alexandrecouture2462]

Very useful info! I'll order one and see if it is fine after.

[@grayfool]

Really learning a lot about Jag heating systems. Thanks.

[@juanballesteros242]

I really want to see the next video related with this problem!! I have the same issue with the 1993 xj40 I just bought.

[@Rick-sl7iw]

Hi Adam as always very enjoyable looking forward to seeing you get to the bottom of this problem

[@philallin5071]

I'm paying really close attention to this repair as I'm gathering info to combat the same problem I'm having with my 1994 XJS.

[@jeffreyprice773]

There is a factory repair kit we used to get to fix that heater control unit, removed the 2 screws on top of the heater control unit from the radio and removed it, open it up and replaced , i can't remember what we did now, but there was a repair kit. Think there's relays inside the blower motor.

[@billnye6533]

I think the kit you're referring to is to replace the micro switch that supplies power to the unit when the knob is in any position other than off. Not a solution for the issues in this video. FWIW, you can get an Osram micro switch online for less than $5, and use $1 worth of miniature machine screws and nuts from the hardware store in place of rivets, to install it. The kit was listed at over $30 when I was looking last year, and I have no idea if they were even available any longer.

[@douglasbuchanan1840]

Can’t wait for more investigation. My 91 Daimler appears to have the same issue with fan only running on high.

[@nsz2302]

Sir i respect you! The amount of problems you put up with would be just to much for me and this coming from an Alfa owner.

[@jeffharrison5265]

Electrical trouble shooting is the one area I hate. A skill I need to work on Good luck!

[@johndavey72]

Thanks Adam .

[@springy-2112]

The resistors 👍🏻☮❤

[@steves4639]

don't know Jags, but whenever i've had trouble with a fan operating only on hi, or on everything but hi, its been the fan relay...rarely the fan motor itself except for once when still running on all speeds but drawing excessive amps

[@maxlindstrom5435]

No fan speed = Bad relay. Only full speed = Bad Transistor.

[@rossbrumby1957]

@@maxlindstrom5435 bad resistor, not transistor. also no fan at all can be motor brushes worn out- had that as well as blown resistor in my Mitsibishi Magna (Australia)

[@pstreetgarage7304]

Great job

[@calinponta6835]

I will add my imput althouht it's based on another car/platform. I own/drive an e32 BMW and had an e34 BMW for a long time. The problem with the fan speeds not working is a fairly common one in that platform and it's caused by a resistor pack that has this exact purpose: to make the fan turn at a lower or higher speed. At full speed the fan works because it bypasses the resistor pack. As i know every car HVAC system works in the same way but i might be mistaken. I would search the manual/look for this part in the investigation.It might be mounted on the wire loom or at the fan itself, but for sure it is not part of the control pannel because of the size and function. It must be cooled somehow and usualy it is mounted directly in the HVAC box for this purpose, to be cooled by the incoming air. Hope this helps.

[@AndyK.1]

Or transistor or FET in more modern tech.

[@eurekax1]

1987 Daimler i need to take out dash to fix ac ,are there any KZbin videos out there shown how it's done Thanks Alan

[@ernstboston8554]

My 94 jaguar had no heat .. fan blower when turn on the heat. No working

[@ernstboston8554]

My 94 jaguar passenger seat not roll back all the way back

[@ernstboston8554]

And also. When check computer reading in the car.. code 2 3 shows.. Don't know what is wrong. Can you help?

[@vinsentsmakaris7692]

Had similar problems (not all speeds, not switching from cold to hot ect), but in my case control module was broke.

[@R.EARNHARDTT]

I have a 1990 Jaguar xj6 sovereign but it has the abs light on is on and my breaks feel heavy af. Some advice would be great

[@gaz1tinsley]

Hi when you took out the stereo panel was there enough room to fit a small amplifire in the cavity ? 7.35" x 2.5" x 1.5" ?? (W x H x D) 181 x 38 x 64 mm

[@MichaTracz125]

I have a question. I have a panel number DBC3225, can I replace it with a panel number DBC5017?

[@Jindra1963]

Hello. I am watching you videos since time ago, I have one XJSC V12 of 1990 on which I have a problem with the missing radio code. Would you have any idea how to fix it please? Thank you for the help

[@LivingWithAClassic]

Radios can be reprogrammed with new radio codes. Some old dealerships can get you the code if the radio is original to the car.

[@Jindra1963]

@@LivingWithAClassic Hello, Thank you very much for your answer. I tried to contact dealers and national Jaguar subsidiary as well as the Jaguar historical vehiculs trust in Coventry UK - Unfortunately nobody can give me the code nor satisfactory answer. If you know how it can be reprogrammed, would you let me know, please?

[@LivingWithAClassic]

@Jindra1963 if you’re in the UK check with Simply Performance. They know how to reprogram them but I’m not sure if they still do it

[@DanielJett]

Hi, Adam. I have a similar problem with my XJ40's fan switch. Speeds Low and High work. Medium is supposed to be an automatic fan, but it only works on Low speed. In order to regulate temperature, I have to manually adjust the fan speed. High fan speed is too loud for conducting civil conversations. I have not yet fixed mine, so I am watching this series with interest. I had a theory thatt maybe the switch was dirty and just needed to be cleaned up, kind of like the electric window switches on your Series 2 XJ6.

[@DanielJett]

Also, I wanted to mention that I have problems with my seat heaters as well, both in my XJ40 and my XJ-S. I would find an episode on troubleshooting that issue worthwhile as well. Thanks!

[@billnye6533]

Both low and high settings are "auto". Low will vary from very low to almost medium, and medium will vary from medium to almost high. If you're getting the same very low/almost no amount of airflow on both the low and medium settings, but can hear a difference in fan speed, you have one fan that isn't functioning on low/medium. There are 2 blower motors, and if only one is functioning, the air from the functioning one will blow accross the dash and right back outside, instead of into the cabin. You can determine if a fan isn't functioning, by setting the fan speed to low/medium, and pulling one blower motor fuse at a time (right blower fuse is in the right side footwell fuse panel, left is on in the left side panel). If you pull the fuse, and there is no change in fan noise, that side fan isn't running. This can usually be fixed by replacing the Darlington transistor on the board in the blower motor housing, and resoldering all the other solder joints on the board. It's a fiddly job, the driver side being more difficult. The steering column is in the way, but doesnt have to be dropped. Only a brace has to be removed. Googling something like "XJ40 Darlington transistor" should get you to some forum posts with information on exactly what transistors to buy, I dont remember the specifics.

[@lauritzpeterholmblad1258]

hey, i have heard that som xj40`s daimlers, have a little red button In the back seat area, wats if fore, i have trying to google it for months but no result hope you can help. sorry for my English i am from denmark.

[@anthonym3769]

So, on my S3, same problem. XJ40 different components, same logic(decision making) going on. Resistor packs rarely fail on older jags, it’s the components which send current to the resistor’s which control fan speed. S3 has 4 solenoids which choose current going to which resistor. I would consult the schematic to trace beginning of “decision” current. For me, I had current(voltage) going to the Fan Relay(probably different component on XJ40) same premise. High speed fan had current exiting going to resistor pack, or the next component “in line” to fan. Low speed had current going to solenoids, but not exiting. Opened it up, solenoid coil wire corroded off for lower speeds. You gotta start at beginning of the source and go to the next component instead of automatically replacing blower fans.

[@earldominguez3938]

I HOUp YO DO AEDEO OF THE XJ 6 MAGASTIC .1992

[@tonysigsby870]

Where do you get all these spare parts might be a good idea let us know and how much for a shop manual which obviously you don't have I guess if you lived in a big city are you could go to the Jag dealer and that is not City It's s h i t e y

[@tonysigsby870]

Maybe easier to figure out what's wrong if you knew what you were doing it doesn't look like you do though

[@billnye6533]

The Delinair HVAC systems in these cars are overcomplicated and very unintuitive compared to most. Lacking a model year specific service manual, it's not easy to find much useful diagnostic information without diving quite deep into forum posts. He's doing what he can with the information he has. Seeing as you've added absolutely nothing to this video but a worthless, snarky comment, it's safe to assume you're completely clueless about diagnosing the issues as well. Surely there must be something else you can spend your time doing, besides acting like a twat in the KZbin comment section.....