Mk4Gaz Posted February 23, 2014 Share Posted February 23, 2014 Hi guys, bit of a new problem here, and unsure what it is ? I was out in the car last week, and the following dash lights started randomly turning on and off, but all together. cat overheat red battery rear light warning yellow oil can I noticed my volt gauge showing only around 13v, so suspected a charging system fault. Anywho, i've replaced the alternator today with yet another new one (I had a print out with it to show it's test results), and although my volt gauge is now showing the correct 14.4v with the engine running, the lights are still on but permanently now ? I've checked error codes, and it's clear. Checked the back lights and they're all good. I know it's charging, pretty sure the oil pressure is good as it runs sweet, and the light doesn't go out if I raise the revs, and I don't have a cat anymore ! Any ideas what the problem could be - far short of a dry joint somewhere, i'm fresh out of ideas ! Quote Link to comment Share on other sites More sharing options...
ghostbuster Posted February 24, 2014 Share Posted February 24, 2014 Have you had the dash out recently, sometimes the plugs on the left and/or right top do not connect properly. Mind you I did have a similar problem when my alternator was slowly conking out with a diode fault. Maybe worth checking the alt on a test bench (even though its a new one). Quote Link to comment Share on other sites More sharing options...
red_zebra Posted February 24, 2014 Share Posted February 24, 2014 I had this when my alternator went where the warning lights didn't go off after the alternator was replaced, had the same warning lights. After spending ages trying to figure out what the problem we started checking the fuses and one had blown, replaced that and everything was fine. I can't remember which fuse it was though but might be worth having a quick check of them, it was one of the small fuses. Quote Link to comment Share on other sites More sharing options...
Mk4Gaz Posted February 24, 2014 Author Share Posted February 24, 2014 Thanks chaps, I'll have a go with the fuses tonight. I've not had the dash trims out for a while, but, because the warning lights are either side, it would be odd for both plugs to not be in correctly - or have a dry joint somewhere? Odd that it was fine before I tidied the engine bay up, then after refitting everything, my alternator packed up. Replaced it with a new one only a few weeks ago, and all seemed fine. Then randomly these lights started flicking on and off, with my voltage gauge flicking between 12.9 and 15.7 with the engine running, so I limped it home, replaced the alternator yet again, and although it now seems to be charging properly, the lights are now on permanently! Bloody cars! Quote Link to comment Share on other sites More sharing options...
Ian C Posted February 24, 2014 Share Posted February 24, 2014 It could be an earth fault. Are any of the lights dimmer than they should be? Check the earth strap under the intake manifold, I had the bolt come out of mine once and the car wouldn't start and those lights you mention lit up with varying brightness. Quote Link to comment Share on other sites More sharing options...
Mk4Gaz Posted February 24, 2014 Author Share Posted February 24, 2014 Thanks ian, interesting as another member has suggested that, it's plausible as I've recently had the inlet manifold off. The lights are all full brightness though. I'll check that tonight too Quote Link to comment Share on other sites More sharing options...
Mk4Gaz Posted February 25, 2014 Author Share Posted February 25, 2014 Well, I've checked all fuses, and all look good. Checked the inlet manifold earth, and that's secure and tight, checked the battery to chassis earth, and that's also good? Any other ideas folks, I'm worried about using the car in case something bad is going on ! Quote Link to comment Share on other sites More sharing options...
markssupra Posted February 25, 2014 Share Posted February 25, 2014 (edited) I had a dry solder joint on the right hand warning lights module. A quick go over with the soldering iron sorted the problem. Other than what else has been suggested, I'm not sure what else it could be mate. Maybe try disconnecting the battery to reset the ECU, I have the Toyota manuals if you need to check anything. Edited February 25, 2014 by markssupra (see edit history) Quote Link to comment Share on other sites More sharing options...
Mk4Gaz Posted February 25, 2014 Author Share Posted February 25, 2014 Right, just been out for a drive, and something definitely isn't right. On first start, it was sitting happily at 14.4v. Soon after leaving home, it dropped to around 14.1 - 14.2, headlights on and heaters on low. I was out for around 15 minutes, and pulled into a garage. Turned the heaters to max, and voltage steadily dropped from 14.1v down to 12.9v within a few seconds. Flicked the heaters off, voltage climbed again. Carried on driving, and a few minutes later, the voltage was up to 17v! It hovered between 16v and 17v for a few seconds, then dropped back down to around 14v. Incidentally, at around 15v all the warning lights went out, then came back on either side of that voltage. Got it home, was out for around 25 minutes in total, and once on my drive, Flicked the heaters back to max, and it steadily dropped to 12.3v before I switched the heaters back off. Also, I noticed that if I put my foot down to accelerate, then voltage would also drop. Does this sound like yet another faulty alternator, the wrong type of alternator, or is there anything else that could be causing this - to do with the car itself? Quote Link to comment Share on other sites More sharing options...
Mk4Gaz Posted February 25, 2014 Author Share Posted February 25, 2014 Should also mention that the warning lights were on the whole time, except for the brief moment when it touched around 15v. And, the master warning light in the middle is also illuminated - didn't mention that before! Quote Link to comment Share on other sites More sharing options...
markssupra Posted February 25, 2014 Share Posted February 25, 2014 I would get that alternator checked, I had a similar problem on another car a long time ago where all the warning lights came on, headlights, dash lights dimmed down and engine was losing power. Iirc, that was the alternator causing the problem. Quote Link to comment Share on other sites More sharing options...
Mk4Gaz Posted February 25, 2014 Author Share Posted February 25, 2014 I think you're right mark, odd that two new alternators are giving me the exact same issue? I've compared my original alternator (oem) with one of the new ones this evening, and the old one is physically bigger, and has a slightly bigger pulley on it. I know the belt isn't slipping, and there is plenty of tension, but I'm wondering if I've been supplied two incorrect alternators? Are the na ones different, apart from the amperage? Would an na one work on a tt? Quote Link to comment Share on other sites More sharing options...
ghostbuster Posted February 26, 2014 Share Posted February 26, 2014 It really does sound like a duff alt AND the wrong one. Quote Link to comment Share on other sites More sharing options...
markssupra Posted February 26, 2014 Share Posted February 26, 2014 I think the NA and TT are different, not 100% sure though. Something is causing the voltage fluctuations, that sounds like the regulator to me. Quote Link to comment Share on other sites More sharing options...
jcbt Posted February 26, 2014 Share Posted February 26, 2014 Gary I think I have an old TT alternator at home which your welcome to try in place of yours. It was changed out due to bearing noise but other than that it worked fine. Quote Link to comment Share on other sites More sharing options...
Mk4Gaz Posted February 26, 2014 Author Share Posted February 26, 2014 Thanks chaps John, that would be excellent, if you don't mind? I'd be really grateful, even just to borrow to test. Could I collect tonight, depending on where you live!? Quote Link to comment Share on other sites More sharing options...
jcbt Posted February 26, 2014 Share Posted February 26, 2014 Thanks chaps John, that would be excellent, if you don't mind? I'd be really grateful, even just to borrow to test. Could I collect tonight, depending on where you live!? Gary no problem - Chris has pm,d you with our phone number - we live near Romford Quote Link to comment Share on other sites More sharing options...
Mk4Gaz Posted February 28, 2014 Author Share Posted February 28, 2014 Well, with a huge thanks to John Bailey, for lending me his spare oem alternator, the car now seems to work perfectly again Straight away, all the warning lights went out, and power is stable, no matter how many electrical items I load it up with. Managed to get my original alternator into a local specialist today, who diagnosed the fault. The internal connection for the voltage regulator had fallen off! 10 minutes, and £20 later, it's all fixed! I'll swap John's alternator back for mine tomorrow morning, and hopefully this saga will be finished. Also, proves the other two brand new alternators I bought, were at fault. You'd never believe it! I think the two new ones were 70A, as they are quite a bit smaller than my stock one. So, I guess they just aren't man enough. Hopefully this thread will help anyone else with a similar problem in the future. Thanks to everyone for trying to help, and again, thanks John for lending me your spare unit Quote Link to comment Share on other sites More sharing options...
jcbt Posted February 28, 2014 Share Posted February 28, 2014 Well, with a huge thanks to John Bailey, for lending me his spare oem alternator, the car now seems to work perfectly again Straight away, all the warning lights went out, and power is stable, no matter how many electrical items I load it up with. Managed to get my original alternator into a local specialist today, who diagnosed the fault. The internal connection for the voltage regulator had fallen off! 10 minutes, and £20 later, it's all I'll swap John's alternator back for mine tomorrow morning, and hopefully this saga will be finished. Also, proves the other two brand new alternators I bought, were at fault. You'd never believe it! I think the two new ones were 70A, as they are quite a bit smaller than my stock one. So, I guess they just aren't man enough. Hopefully this thread will help anyone else with a similar problem in the future. Thanks to everyone for trying to help, and again, thanks John for lending me your spare unit No problem Gary glad you got it fixed See you at Bluewater next Friday Quote Link to comment Share on other sites More sharing options...
Mk4Gaz Posted March 1, 2014 Author Share Posted March 1, 2014 Ok, scrap the above, it still doesn't work I'd fully charged the battery, and after driving for 10 minutes, all the warning lights are back on, despite showing a reading of circa 14v. As soon as I load it up with heaters on full, the voltage drops, and continues slowly dropping, and when I turn them back off, it clubs back to around 14v. I think the fully charged battery bought me false hopes, and took around 10 minutes to lose enough charge to trigger a fault. That's now 4 alternators, two of which are brand new. It's definitely charging, but clearly the car is drawing too much power. There must be something more sinister at play, but I'm buggered if I know what it is. Is there anything that anyone can think of, it must be something so simple? Quote Link to comment Share on other sites More sharing options...
jcbt Posted March 1, 2014 Share Posted March 1, 2014 Sorry to hear that Gary How old is the battery could it be that as its not holding charge? Quote Link to comment Share on other sites More sharing options...
Mk4Gaz Posted March 1, 2014 Author Share Posted March 1, 2014 Sorted, I think! Poxy bad connection on the alt sensing wire, from the 3 pin plug - white wire. Been messing around with it all morning, and it appears that it randomly loses contact, due to a dodgy pin. I've ordered a brand new denso plug, sonim hoping a quick rewire will sort it out finally. Quote Link to comment Share on other sites More sharing options...
rider Posted March 2, 2014 Share Posted March 2, 2014 Reading up about automotive alternators online there is mention of... "Modern designs (since circa 1990) do away with the voltage regulator altogether; voltage regulation is now a function of the electronic control unit (ECU)." Quote Link to comment Share on other sites More sharing options...
fastphil666 Posted June 19, 2019 Share Posted June 19, 2019 Hi gaz, i know this is years old but i have the same issue. Same lights but no random drops in voltage to report. Instead when i give the car some welly and get full boost, i get the same warning lights! When running around on first turbo, no issues, turn off ignition and back on, no issues. Im wondering if its an earth now or possibly the same white cable?? Quote Link to comment Share on other sites More sharing options...
Mk4Gaz Posted June 19, 2019 Author Share Posted June 19, 2019 Hi gaz, i know this is years old but i have the same issue. Same lights but no random drops in voltage to report. Instead when i give the car some welly and get full boost, i get the same warning lights! When running around on first turbo, no issues, turn off ignition and back on, no issues. Im wondering if its an earth now or possibly the same white cable??Hi mate, have you checked for ecu error codes? Mine was simply a dodgy wire on the 3 pin plug, randomly making and breaking connection. Happy to report that I've not had any issues since fitting a new plug all those years ago. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.