Odd- installed new radio with constant n switched power connected to fuse box (fused to white n brown wire connections). NOW when I press on brake pedal, the switched power seems to get interrupted for a second- n radio reboots. It maintains station memory. Brake lights n all work fine but I do have a battery drain I plan to trouble shoot. Everything electrical works even horn, signals, wipers, dash…) thanks guys.
That looks like a retro sound …. If it is you need to connect to a live ( all the time) fused wire already in the loom of the radio , then the other wire is switched via the ignition on position …… hopefully this will help
Red wire- switched to white wire on fuse box. Yellow wire (constant power) to brown at the fuse box. I did that. N then rechecked it- same thing
Which fuse?..
Ok so what is happening here I think is that the red wire should also be fused and go to a spare terminal on the green side of the fused white…. Some radios are very sensitive to voltage drop so if your battery is not up to standard the additional drain on the circuit may be the issue otherwise I’m stumped
Thx guys I’ll send photo of fuse set up.I think the drop in voltage makes sense bec I have to keep charging the new battery. It never goes above 12v on meter just to 11 n below. I’m going to check alternator n relays n VR once I figure out how.
Add: yellow on #3 fuse, red on # 6
Given everything you’ve written the voltage drop theory would make sense.
I had charger on battery- no problem- then disconnected n put on lights n pressed brakes- flashed off- so that goes to it being a temp voltage drop as the cause- now on to see what’s causing that- a symptom of something larger- charging system. Alternator looks pretty new
My battery when charged has 12 volts.
When checking voltage at alternator with car running at 1500 rpm - voltmeter red on batt terminal ( with battery wire off) n black on alternator bolt for ground- zero volts. When all was connected n running it read 12 volts with no change between battery terminals n alternator terminals. So despite alternator looking new it’s done?
Electrical problems are tough. I would recommend motor age training videos. It’s a professional series that is well worth the time it takes to watch. Watch one episode and I guarantee that you will watch more. Be ready to spend a few hours. The voltage drop testing is particularly helpful.
Chris- Looking at your photos it looks like someone in the past has done a lot of non-Jaguar electrical work on your car. The condition of the wires at the back of the alternator is one indication. However one thing I noticed should be of concern to you- the insulation on blue wire in one of your photos appears to be burnt, a very worrying situation:
This is the wire that runs from the headlight switch in the center instrument panel to the dip switch to the left of the steering column. This is a large gage wire so it would take a considerable amount of current to do this.
I would remove the battery from your electrical system and do a complete visual inspection of all electrical wires and connections. Every connection should be disconnected, cleaned, and reassembled with dielectric grease and verified tight. I know this is a lot of work but if you have a car fire the work load will go up exponentially. JM2¢
Thanks Doug- it’s too good of a car to burn up! Great advice!