Welcome to our Site for MG, Triumph and Austin-Healey Car Information.


TR parts and Triumph parts, TR bits, Triumph Car Spares and accessories are available for TR2, TR3, TR3A, TR4, TR4A, TR5, TR6, TR7, TR8, Spitfire and Stag and other TR models are available from British car spares and parts company LBCarCo.

Triumph TR6 - Still Have Battery Drain

Referencing my archived post, I checked the trunk driver-side rear chasis-ground wire behind the trunk trim and it is black. (Actually it's 2 black wires from the harness going to the spade).

I've also performed "the quick" load test. Once the neg. terminal was disconnected (battery fully charged), I still have the "small spark" when the neg. cable is put on the post when the alt. is unplugged and even if all 3 fuses are removed at the same time as the alt cable.

I had a shop validate that the (Interstate)battery is holding a charge.

The alt. does appear to be providing a charge, but the battery is drained after about 2 days of the car sitting.

I do have an alarm and power amp installed, but if I leave the alarm off (and the power amp is not on when the car is turned off), I wouldn't imagine that the radio's memory settings and clock would draw it down after only 2 days (perhaps 2 weeks).

Please provide suggestions on next steps. Could it still be the alt? I'm willing to get it r&r'd, but only if it (truly) needs it.

Many Thanks,

P Johnston

Next Steps:

With the alt. unplugged, I'll hook-up the neg. terminal (to the fully charged battery) and leave it for a couple of days. Then re-connect (isolating the battery 1'st), and see if it starts.

Hopefully this will assist in determining if it is a short in the alt.

P Johnston

Hey, Peter. Be sure and do the same with the power amp (is it an auto-on model?) and alarm, one at a time. I had a radio that sucked down a battery in 2-3 days with the channel memory. Never thought it would have happened, but after disconnecting it, no problems. Just have to reset the stations if I don't drive after 2 days...
Brent B

Sorry Guys,
I don't buy the radio thing....My Am-Fm Cd player has 24 preset stations and a clock and I can leave it for weeks and she starts no problem I think you have a drain and it's not the radio..
Charlie Ballard

Charlie - I guess your post is directed to me and my old Denon radio. Most likely the design's have changed over the years (it's 14 yrs old), but my drain was most assuredly from the lead to the memory. My point was make no assumptions - test everything one at a time.

Brent B

QUOTE:"I still have the "small spark" when the neg. cable is put on the post when the alt. is unplugged and even if all 3 fuses are removed at the same time as the alt cable."

The are only 2 things left to look at if you still have a spark (DRAIN) if all above is disconnected.
The starter motor solenoid has a direct connection to the + BAT. terminal. Also the ignition has a direct connection to the battery. Try removing the large brown wire to the starter and see if you get the spark or not.
Rick C

PS Brent, time to get rid of the 8 track:) Yes modern car radios will draw in the very low mili-amps. Tube radios went out with the 8 track.
sorry Brent..just havin' fun with ya:)

Rick Crawford

Hi Brent,
Sorry.. no..not at you..just at the problem !! haha..I'm just amazed that a clock and presets would drain that much in a short time..I really think something else is at fault..even batteries can be bad when they appear to be ok...Can you try switching Batts with another car ??
Charlie Ballard

Will eliminate the radio in testing just to be sure. Can't be the amp nor alarm (re: comments above).

It's just possible that it may be the starter. It was replaced with a refurbished unit about 4 yrs ago. Seems to work fine to crank, but I will remove the brown wire & check for spark (once I double check the alt).

I do have a Crane electronic ignition that's been installed for about 10 yrs now (external balast).

The Intersate battery is a "good one."

At this time, the car cranks fine when the battery is fully charged. It's just this annoying "2 day drain."

Thanks to all, will post back in a couple of days once I've completed further diagnostics.

P Johnston

Peter, If my assumtion is correct that your car is a late model TR6, I may be able suggest a possibility that hasn't been raised as yet. My '74 exhibited symptoms very similar to yours. I tried many of the same diagnostic procedures described in this thread. In the end I gave up and took the car the car to my mechanic who successfully cured the problem. The current drain was caused by a frayed wire which was part of the original (long since disconnected) seat belt buzzer system whose disused wiring had been laying dormant under the seat until something disturbed it and put a bared wire in contact with the floor pan. Before I got it fixed my battery would always be completely flat within a couple of days unless I disconnected it.

Just an idea....
Pat Bishop

Peter, if you have a digital volt meter, you can isolate the problem. If you don't have one, you can purchase a cheap meter for under $30. You first need to identify how much current drain that you actually have. This can easily be done by connecting the meter to read amps in series with the battery cable. With the ignition switch off and all lights etc off, you should have zero current draw, unless you have a radio that has a built in clock, then the current draw should be a few milliamps, so you will need to go to a milliamp scale to read that. If on the other hand you are seeing a current draw of .5 amps or higher, you will need to start isolating the drain to the problem circuit. Here you will need to disconnect various wires or fuses and again place your meter in series with the fuse or device until you can locate the problem device or circuit. This is a little time consuming, but it is the only way to isolate the problem. Some problem things that I have ran into have been shorted starter solenoids, alternator (including the R/R unit) wiper motor, radios, and the good old electronic ignition system. Hopefully, you will find that it is a frayed or cut wire going to ground,which is pretty common on older cars like ours. I would take a close look at the fuse panel and the wiring through the firewall gromets, before going too far. Good luck in finding your problem. Persistence will pay off.
Arnold Newton


Great suggestion. I will most certainly check those wires beneath the seats. They were disconnected (by my father) about 1 week after he purchased the vehical (in 1975).

The seats have been out a few times (for r&r, running stereo wiring, and installation of modern seatbelts).

Arnold, I do have a digital volt meter, and I have proceeded with the diagnostics, although unsuccessfully so far.

Thanks to all again. I will keep you informed.

P Johnston

Ok, some clairification & inspection comments, & questions.

1'st to clairify. The orig. seatbelt & sensor plugs under the seats were disconnected when I r&r the seats. The mult-wired seat belt buzzer plug was removed from the buzzer socket back in '75. This plug is still intact, just not plugged in.

2'nd, comments. One of the black wires from one of the seatbelt plugs was squished under one of the aftermarket (static) seatbelt mounting hardware, but it does not appear to have been frayed. Anyway I have nipped & capped these wires so they won't be an issue anymore (I hope). I know the purists must be cringing, but hey, no big deal to me (unless of course I still need to twist some of these wires together, which I can do if necessary).

The iginition light illuminates when the engine turns over. I've been told that if this bulb is burnt-out, the alt. will not charge the battery. Fact or fiction? Doesn't matter at this time because it's working.

3'rd, questions. I'm assuming that it is ok to have the seatbelt buzzer plug remain out of the socket, being that it has been that way since "Week 2." In one of the archived posts, there was something written about 2 wires needing to be twisted together to bypass the buzzer. Please confirm my assumption that this mult-wired plug can simply remain unplugged from the buzzer socket.

Also, for many many years I recall that a White/Pink Stripe wire with female (rubber) socket that comes from the harness behind the interior reostat has not been plugged into anything. Several years ago as well as today, I've looked to see if there is a male-ended wire that this possibly belongs to, but have not found one. All wires behind the dash appear to be where they belong (except for this one). Can anyone shed some info about this (lonely) wire?

Thanks all.

P Johnston

The white covered TR6 Repair Operation Manual, pages 86.00.02 & 86.00.03 confirm that the White/Pink Strip wire is Radio Supply, so no problem there.

By the way, the car is a '75 (actually if I recall, a '74-1/2, forget where I got this from).
P Johnston

I found the archvied thread I was refering to (above).

Don Masters wrote (Oct. 22, 2003):
You'll also notice that your car has a seat belt interlock. The seat belt control module is mounted in the passsenger footwell, near the battery box. If you wish to bypass the seat belt controls (recommended, as they give a lot of trouble), just connect the white/red and the white/orange wires together at the seat belt module. If you look at the '75 wiring diagrams, you'll find that's just what the factory did in '75 in response to customer complaints. This may solve your problem.

Now as I mentioned, this has been unplugged since "Week 2," so I'm not thinking that this is causing my problem.

Also, as mentioned above, I nipped the seatbelt & sensor plugs (back towards where they splice off the harness going to the rear). Can these wires remain nipped, or do I have to twist some of them together?
P Johnston

Looks like someone knew what they were doing back in '75, because the white/red & white/orange wire are already connected using a snap-on type connector.
P Johnston

Well it's fixed.

Don't know if it was:

a) Putting the seat belt module back in the socket (probably). I believe my comments above were wrong when I said that this had been disconnected from "week 2." I believe that only the seat belt wires (under the seats) had previously been disconnected by my father.

b) Questionable battery (also probably). Battery was 24 months old (under pro-rated warrenty). Thing is the when the battery was new, I was still having this problem. Perhaps this issue for the past 2 years caused it to go bad.

c) Clipping-back the seat belt & sensor wires (info above).

Thanks to all.

P Johnston

This thread was discussed between 25/05/2004 and 04/06/2004

Triumph TR6 index