the question i have is the terminus of the green/black wire. can't seem to find it on the wiring diagram, which shows the SW being the feed to coil and black being the CB side, but no green/black any where near the coil. As is it's not correct i believe. i'll be converting the car to neg. ground to accommodate a radio, FYI . ps the white wire seems to go to the sender on the thermostat housing and then back again on same color wire into harness (which BTW is wrapped in electrical tape before entering the trunk harness (wrapped in cloth).

 

Point out where on the wiring diagram you have a problem. There are sometimes a number of jump points on the way to a device but the diagram is generally correct in my finding with my re-harness.

Sorry ~ having attachment problems ~ go here ~ Can't reload/upload pdf.

https://www.jaguarforums.com/forum/m...8/#post1971413


https://www.jaguarforums.com/forum/a...ram-hi-res.pdf

 

BTW ~ If a radio is your only concern you don't have to change the car to negative earth. You can simply use a polarity inverter if the radio is not switchable polarity.

 

thanks glyn - that's the diagram i'm using. have a pdf that i can zoom on, well i might consider the inverter. i have a few wires dangling in the bay. i'll review the diagram again and see if i can spot that green/black attaching to anything in the bay. - stu

 

The green/black wire goes to the choke (enrichment carb) Otter switch on the diagram.

As it does here if you download & zoom this pic.

 

Tired old original car. Green & Black wire to Otter switch.

 

Gley you may use an inverter but most radios use the chassis as earth. If this is the case thr radio chassis must be isolated which of course would eliminate the need for an inverter.

 

Not so. You have to consider that the antenna has to be grounded to the car body. Etc.

A little edification from our friends at the MG Forum saves me the job.

https://mgaguru.com/mgtech/electric/et207.htm

 

Nice article and the only pare is the "possible" with the antenna or the keys etc hitting. There are many Jaguars (+earth) that have isolated radios and have not switched polarity. However the best solution is to find a switchable radio. Sorry the little edification was little and does not match actual applications.

 

The "little" edification is very good & it is plain that you have not fully understood it. It is the right & safe way & what many of us do. It exactly matches actual applications. In fact I have a hybrid of switchable radio but modern amplified hidden antenna with a voltage/polarity inverter.

 

Please also understand that for a monopole antenna, as most use on classic cars, that such an antenna requires a "ground plane" for maximum efficiency. Having a ground plane effectively gives you a dipole that potentially doubles the antenna output/effective length. Isolating things effectively hobbles antenna performance.

 

The article is completely correct George, and is the correct solution to this problem, if you don't think it matches actual applications then you do not understand the basic principles of electrical circuits, or the potential risks of getting it wrong.

Isolating a radio from the chassis carries far more potential risk and also a dead short through the aerial is this is not dealt with properly, the voltage converter is a good solution for those that do not wish to change polarity from original and change the clock polarity

I guess if you don't understand the article at all then it would not be edifying for you George, and your comments are certainly not edifying.

 

Would such a voltage inverter be suitable for a Sat-Nav, which are of course negative earth, as are assorted players.

 

If the Sat Nav you mention is a stand alone unit (the type you stick on the window of the car) then it has no chassis ground and you can simply wire up the plug the opposite way. If you are using the Cigar lighter to power it, you connect the positive to the outside connection and the negative to the centre pin and it will work on a positive ground Cigar lighter socket (make sure you mark up the plug so it does not get used on a Negative earth car).

If you want to use a built in Sat Nav with a grounded chassis then the inverter will work for that.

 

Well said Sir!