Farmerfred Posted June 29, 2013 Share Posted June 29, 2013 Hi all. This is the scenario. Remove non-descript cassette radio, fit stereo CD. Wiring to old unit, permanent live, earth, left and right speaker connected to stereo wiring by means of one of those joiners that you buy in a strip and cut to suit either as a block or single, no plugs or bullet connections. I've wired in the new stereo using an adapter plug to the unit and wiring the tails as per the wiring instructions and all is working. Now this is the problem, when I turn on the lights the power to the unit is interrupted, this happens when the lights are firstly switched on and every time you switch from both dip and main beam. My initial thoughts are that the permanent live from the vehicle that is used for the power to the stereo is coming off the lighting circuit somewhere and needs to be coming off something else to eliminate this. The Vehicle is a Defender 90 County 300TDi 1995. Any thoughts? Quote Link to comment Share on other sites More sharing options...
Mutley Posted June 29, 2013 Share Posted June 29, 2013 Hi i did the same job on my LR some time back also a 90 300tdi '95 took the perminent live from the Batter, drilled a small hole in the passengers side of the seat box, close to the floor as you can and tiight up to the gear box tunnel. Fed the perminent live wire from the battery through the hole along the passengers side floor under the mats, slackened off fuse box tray fed the wire behind the fuse box, tightened up fuse box then found a gap into the dash fed wire up into the dash and all was good, nice and neat with no wire showing. Hope this helps? All the best Mutley Quote Link to comment Share on other sites More sharing options...
Farmerfred Posted June 30, 2013 Author Share Posted June 30, 2013 Thanks Mutley. I was thinking that I would need to give the unit its own direct power feed so you've confirmed my plan of action. I'm also going to, although there is one in the rear of the unit, put in an in-line fuse for added protection and that can go either in the battery box or in the fuse box area. I'll have a go later on and report back. Quote Link to comment Share on other sites More sharing options...
Aragorn Posted June 30, 2013 Share Posted June 30, 2013 Use a multimeter to see what each of the power feeds is doing when you turn the lights on... If the head unit has an illumination feed, remove it. Check the ground connections are good too. Quote Link to comment Share on other sites More sharing options...
Farmerfred Posted June 30, 2013 Author Share Posted June 30, 2013 Been addressing the problem this afternoon and the results are, same thing happens wherever the power feed is taken from, original radio feed, ignition, fuse box and direct from the battery. However, I think I may have stumbled upon what may be causing this problem and that is the lighting relay for the front spots has rusted up and is not clicking and with my tester is showing power leakage to earth. I'll know for sure when I'm able to get a new relay and try it again. Quote Link to comment Share on other sites More sharing options...
western Posted June 30, 2013 Share Posted June 30, 2013 just pull the 12v feed off the spot light relay & safely isolate it for now. that should let you confirm the radio is wired up & fully functional. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted June 30, 2013 Share Posted June 30, 2013 Sounds like your stereo earth could be connected to a switched feed to the lights -when they are off, it's earthed, on it goes to 12V, and hence no power? Quote Link to comment Share on other sites More sharing options...
Aragorn Posted June 30, 2013 Share Posted June 30, 2013 Is the stereo going off, or just bouncing off and back on? If its bouncing off and back on, its most likely an earthing issue. When you turn on the lights, theres a momentary high current draw as they "warm up", if theres a bad earth, this high current draw can cause the earth potential to rise above 0v, which your stereo will "see" as a voltage drop and shut off. Quote Link to comment Share on other sites More sharing options...
Farmerfred Posted June 30, 2013 Author Share Posted June 30, 2013 This is what's going on now. Relay for spots has been chucked, spots not effectively wired in. Turn radio on, working, switch lights on, radio goes off momentarily and then resumes, switch to main beam, radio goes off for a moment, switch lights to dip, radio goes off again, radio comes back on, switch back to main beam radio stays on, back to dip, radio stays on, leave lights and radio on for 30 seconds then dip/main beam and radio goes off again as before and also when you 'flash the lights. The radio is wired as the old radio cassette was, using the existing wires from the vehicle and new radio/CD has been wired as per the instructions. It's wired very simply in that I'm only using the right and left 'front' speaker wires from the unit, permanent live to unit, which involves 2 wires from the unit, 1 for the 'memory' and the second for on/of button. It may be that the unit needs a better earth point itself or I've connected a wire that should not be connected or have connected it to the wrong point. I'll keep at it until I beat it. Quote Link to comment Share on other sites More sharing options...
Retroanaconda Posted June 30, 2013 Share Posted June 30, 2013 Check your battery connections. I once had a very loose earth clamp on the battery post and the symptoms were the radio cutting out when electrical loads such as brake lights/indicators were applied. Quote Link to comment Share on other sites More sharing options...
Farmerfred Posted June 30, 2013 Author Share Posted June 30, 2013 Checked battery terminal leads when trying a feed from the battery, they're ok. Indicators and brake lights don't affect it. Also thinking that the vehicle headlamps/connections may have something to do with it if they are suffering a less than adequate earth but I can't see that might be the case as they work ok but if I knew where the headlight units were earthed I'd check them out just out of curiosity I've been out since my last post and again checked the connections and all are as the instructions but still for the life of me don't understand why switching on and in using the lights knocks it out momentarily and the same when power is taken direct from the battery. Quote Link to comment Share on other sites More sharing options...
Aragorn Posted June 30, 2013 Share Posted June 30, 2013 the issue has to be between the battery and the chassis/bulkhead. As a quick check, disconnect the existing radio earth, and instead run a wire straight to the battery negative and see if the issue goes away. Quote Link to comment Share on other sites More sharing options...
Aragorn Posted June 30, 2013 Share Posted June 30, 2013 but still for the life of me don't understand why switching on and in using the lights knocks it out momentarily and the same when power is taken direct from the battery. I tried to explain it above, the issue isnt the power getting TO the radio, its the power getting FROM the radio back to the battery thats the issue. If you imagine, at the radio power in is 12v, and "earth" is 0v Bulbs draw a large current when they're cold, and as they heat up to "white hot" their resistance increases and the current draw drops and stabilises. If theres a bad earth connection between the lights and the battery, then when the lights first power up and draw that huge amount of power, it gets "stuck" trying to get back to the battery via the bad connection. This raises the voltage of "earth" from 0v to some higher figure (lets say 4v for arguements sake) If the radio is sharing that same earth path, then when you click the lights on the radio sees 12v on its power in and 4v on its "earth", however the radio simply assumes earth is 0v (it has no other reference to tell it otherwise), so the 12v on the power in "appears" like its only 8v, so the radio powers off. After a moment, the bulb current draw drops to normal levels, and the "earth" potential drops back to 0v like it should be, the radio sees 12v again and turns itself back on. Any clearer? Quote Link to comment Share on other sites More sharing options...
Farmerfred Posted June 30, 2013 Author Share Posted June 30, 2013 That seems to be a pretty good analysis, I'll wire in an independent earth to/from the unit, using a heavier gage than the 'normal' earth wire and see what that does and report back. Thanks all thus far. Quote Link to comment Share on other sites More sharing options...
DaveSIIA Posted June 30, 2013 Share Posted June 30, 2013 Have you checked the earth lead from the battery, via the chassis tag to the gearbox? The tag to the chassis can work loose under vibration and give a poor earth to electrical equipment grounded through the body, while maintaining a good earth to the engine/gearbox for starting. Will give similar symptoms those described. Quick check is to clip a jump lead from an earth point on the bulkhead to the negative post of the battery and test radio, lights, etc. Quote Link to comment Share on other sites More sharing options...
muss12 Posted July 1, 2013 Share Posted July 1, 2013 Well this topic has saved me asking the same question again, I've got the same problem but mine also goes off when braking sometimes and when you indicate aswell! maplins here I come Quote Link to comment Share on other sites More sharing options...
fearofweapons Posted July 1, 2013 Share Posted July 1, 2013 When I got my 110 it had no radio so I wired one in. I saw the exact same symptoms as many have described here, wehen I braked, used the indicators or headlights the radio would momentarily turn off and then back on. This was traced to a faulty earth. Once that was fixed the stereo has worked as intended. So I would either run a dedicated earth for your radio or, better option, find the faulty earth and fix it as it will cause problems further down the road. Quote Link to comment Share on other sites More sharing options...
Farmerfred Posted July 1, 2013 Author Share Posted July 1, 2013 I have with a friend just spent the last hour and a half trying various tests and changing out and adding in earth and live feed wires as has been suggested, still does exactly the same. However, with lights on and engine running radio goes off as before but if you give the engine a bit more revs off tick-over the radio unit stays powered but if you pull the lighting stalk back to 'flash' then power is interrupted. I have also fitted a new driving lamp relay and with the lights on full beam and spots on power to the radio is lost completely. So, the conclusion is that the lights are drawing the current and the first 'donor' of required current is the radio unit or there is still an earth issue which has to be somewhere in the lighting circuit. Brake and indicator lights don't affect it. The puzzle remains, for the moment. Quote Link to comment Share on other sites More sharing options...
Maverik Posted July 2, 2013 Share Posted July 2, 2013 Try putting a temporary earth wire directly from the left hand headlight earth back to the battery and see what happens... I've been having some on-going earth issues and tracked it back to the "body earth" of the wing itself - mine manifest itself as a wiper fault, I wonder if yours is coming up where your radio is earthed. Mav Quote Link to comment Share on other sites More sharing options...
Farmerfred Posted July 2, 2013 Author Share Posted July 2, 2013 My next point of investigation is going to be the headlight circuit, particularly the earth points, there is what they call a 'header point' on the bulkhead that could hold the key. I think that the issue has been there for some time and in fitting the new radio unit has made it more noticeable, I have noticed on the odd occasion when driving at night in the rain that when the windscreen wipers move the headlights very slightly dim but this may be totally unrelated. Thanks for the suggestions so far, I'm trying them all and then some. I'm sure we'll sus it eventually, keep thinking. Quote Link to comment Share on other sites More sharing options...
Aragorn Posted July 2, 2013 Share Posted July 2, 2013 I have noticed on the odd occasion when driving at night in the rain that when the windscreen wipers move the headlights very slightly dim but this may be totally unrelated. Its very likely its the same issue. Quote Link to comment Share on other sites More sharing options...
Farmerfred Posted July 3, 2013 Author Share Posted July 3, 2013 Got back to trying to sort this out earlier, last resort, wired power feed positive and earth negative DIRECT from the battery, this bypasses all other wiring in the vehicle and makes the radio unit independently powered. Outcome, IT'S WORKING!! No more power interruptions when switching light positions and the radio stays constantly powered up until you switch it off. Many thanks to all who contributed to this, your advice and input has been much appreciated and valued and I hope that it has also been of help to others who have been and still are suffering the same problem. Thank you. Quote Link to comment Share on other sites More sharing options...
Maverik Posted July 3, 2013 Share Posted July 3, 2013 Hehe, hmm just be careful, the problem might surface again and bite you in the bum a little harder next time but glad you got your tunes working, I'm just waiting for some speaker foundations to be delivered so I can upgrade the 110. ironic really not that you can hear so much from the radio over the din of the engine and the odd rattle and bang of the other "land rover noises". but it was high on my list of "to do" before I took the truck any long distance. Mav Quote Link to comment Share on other sites More sharing options...
Farmerfred Posted July 3, 2013 Author Share Posted July 3, 2013 I think it was directly earthing it from the battery that cured this particular problem. If I get any problem from the lights then all earthing points will be investigated if and when. Quote Link to comment Share on other sites More sharing options...
Aragorn Posted July 3, 2013 Share Posted July 3, 2013 I thaught you tried that earlier and it didnt work? Quote Link to comment Share on other sites More sharing options...
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