Slow Turn signals.....

[Nunyas]

I'm having this electrical problem with my '76 B that I can't exactly pin point (it's been there since i got the car). Since I do most of my driving during the day light hours the issue has slipped to be back of my mind til lately (it's getting darker and darker when I leave work now). The signals seem to work 'ok' during the day, but are sometimes a little sluggish, usually while braking. I replaced the battery recently, and did a multimeter check on the voltages. With the car off I measured just over 12V across the positive terminals. With the car running I measured just over 13V across the terminals. I interpretted the increased voltage to mean that the alternator is working. However, since I'm having to drive increasinly in wet or dark conditions I have to use more of the car's electrical system. If I have the wipers or headlights on, I find that the blinkers/turn signals will come on but won't begin flashing for several seconds (close to a minute). Yesturday I had to drive in the dark and I noticed that my red 'dummy light' was dimly lit and got slightly brighter whenever an additional electical part was activated.

I haven't checked the voltage with the car running and all the electricals going at the same time yet, but I have this hunch that the alternator may not be totally up to par anymore. Am I correct in thinking that the source is the alternator? Or is there something else that could be at fault here that I should check before I go running off to find a 'high current' replacement?

 

[Cottontop]

I'd look at the most obvious things first and replace the cheapest things first.

Most turn signal flasher units work by by passing current through a coil of wire that is wrapped around a bi-metallic strip.

While the current is passing, the signal light is on. When the strip heats up, it bends and opens a set of points, turning off the signal light and stopping the current from heating the coil.

This allows the bi-metallic strip to cool, straightening the strip and closing the points. This cycle happens rapidly.

In my Healey, the flasher actually trips a relay and does not directly turn on the light. The flasher does however, activate the dash indicator light.

If your flasher is original, the points are probably burned and pitted, resulting in a high resistance. This is probably why your flasher takes so long to start flashing and the dash indicator light is very dim.

I'd try replacing your mechanical flasher with a newer solid state unit. They only cost a few dollars and have a solid state clock operating solid state relay points. There are NO mechanical parts to wear out.

This type of flasher is usually not affected by a slightly less than optimum battery or alternater voltage.

If that doesn't fix the problem come-on back or someone else may have another idea.

 

[Dave Russell]

[ QUOTE ]
Yesturday I had to drive in the dark and I noticed that my red 'dummy light' was dimly lit and got slightly brighter whenever an additional electical part was activated.

[/ QUOTE ]

[ QUOTE ]
If your flasher is original, the points are probably burned and pitted, resulting in a high resistance. This is probably why your flasher takes so long to start flashing and the dash indicator light is very dim.

[/ QUOTE ]

CT,
I thought that he meant the red charge indicator, not the green turn pilot lamp.
D

 

[trrdster2000]

Before you do anything else, check the grounds on all the bulb units, they give the same indication if bad, (slow flashing), even if just one on each side is bad. Wayne

 

[Bret]

Yes, it sounds like your alternator could be the source of the problems you descried.

Just so you know the red dummy light (however dimly lit) is an indication that your charging system isn’t working as good as it should and will gradually get worse as time goes on. Yes it could indeed be time to replace the old alternator, but I would try a couple of things first before you drop the cash.

Here is a test I like to do: Take off the lid to battery compartment and attach your voltmeter to the terminals. Position the voltmeter in an easy place to view & monitor the voltage safely while you are driving. Now start turning things on one accessory at a time to increase your power consumption. If the voltage drops below 13.0 volts then your car’s Alternator isn’t putting out.

But before you write off your alternator try some cleaning first. Take a wire brush to the battery cables & terminals. Clean the connector & terminals on the back of your alternator itself. Also it might be a good idea to clean the cables going to the starter while your at it. If after all that you still have a problem take the alternator to a local auto parts store to be tested (usually a free service). If it checks out ok – then I’d look at the cables between the Battery & the Alternator. A old corroded cable could be the cause of the problem. With the engine running measure the voltage between the negitive terminal of the battery to ground - it shold be less than a 0.5V. Likewise measure the voltage between the positive battery terminal and the back side of the Alternator. If more than a volt then you have a high resistance cable. You might have to re-terminate some cables.

But if the Alternator fails the test - you will need to order a new one or perhaps consider doing one of the Delco Alternator (higher current) upgrades that a lot of MGB folks are doing these days.

Good Luck!
/ubbthreads/images/graemlins/cheers.gif
Bret

PS There are a few good tech tips & tests that I recommend in the back your Moss Motors Catalog that might help.

 

[Nunyas]

Thanks for the tips guys. I was indeed speaking of the "charge indicator", and it's so dimly lit that you can only see it when it's dark out. I'll have to fabricate some leads for my DMM that'll reach from the engine compartment to the battery to be able to test the voltage drop across that line. Hmmm...on second thought, I could probly measure the voltage at the alternater and compare it to the voltage across the battery terminals, and if the cables are good then the voltages should be nearly identical.

I had to drive home in the rain tonight, and it was about 2 steps away from being a full blown adventure. With the sun setting and the rain falling I had every electrical component turned on, except the defroster (the fan/switch isn't working). The first thing I noticed tonight after starting my car is that it wants to die when the wipers are turned on unless the engine is kept above 2000 RPMs, at least until the engine had fully warmed up.

Also, I guess my wiper switch isn't hooked up properly or has the incorrect switch installed. The wiper switch pushes foward like a turn switch going into 'high beams'. The 3 up/down positions of the wiper switch work as follows on my car: 1) (top most position) puts the wipers in the down not in use position; 2) (middle position) stops the wipers where ever they are on the wind shield, and leaves them there; and 3) (the bottom most position) the wipers seem to operate at normal speed.

I'm guessing that the wiper switch and how it operates the wipers is not entirely related to how the car is running, but there seems to be some sort of connection between the two since the car wants to stall when I turn them on and the engine is still cold.

 

[AlamedaMGB]

Had a similar problem once.. after I cleaned all my connections and still had the problem, I adjusted my alternator belt..

Sometimes the cheapest and easiest things work.


but you definitely have a charging problem.. start at the alternator and work back from there. You should get over 13 volts at the alternator .

good luck

 

[Nunyas]

where does one find one of these solid-state flasher machanisms? I've googled for it a few times but have only come up with totally unrelated stuff...

 

[Cain]

Nunyas,

I replaced my Lucas flasher unit (in my TR6) with a solid state flasher unit from Autozone. It was like $2-3 and works like a charm. Don't know if you have Autozone in CA, but I'm sure other discount auto part places have the the SS flasher units.

 

[lesingepsycho]

I just had a similar problem with my Midget. The 'red dummy' light was coming on but the car seemed to be running fine. I replaced my flasher unit, moved the battery to the trunk, cleaned all the terminals, put a new heavy gauge wire back to the battery and the red light was still coming on despite all this. Also did the multimeter check and read about 13v. The car never had starting problems or any particular problems while driving so, like a dummy, I ignored the dummy light dismissing it as some other malfunction, afterall, if it where a charging problem, it wouldn't be long until I had starting problems. Well it was long and just long enough to almost get me in trouble. As I was coming home one night, the car started cutting out unless I kept the RPM's ultra-high. Luckily I was able to get the car home practically red-lining it all the way. When I finally got to the stop-light directly in front of my house no amount of revving could keep it going any more and luckily there was a nice military guy in his fatigues behind me that helped me push it through the intersection and into my drive-way. So really I dodged a bullet because I should've just replaced the alt to begin with but didn't because the factory lucas was like $140. But I'll tell you, if I would've been stranded in the middle of no-where with a dead Midget, that $140 bucks wouldn't have seemed like so much. Learn from my (near) mistake!! /ubbthreads/images/graemlins/nonono.gif

 

[Nunyas]

wow... Sounds very similar to the problems that have been plaguing me for a while. I have to keep my RPMs up over 1500 in order for the car to use any of its electricals without stalling. For example, at idle under 1000 the car will stall if i turn on my wipers. It will also stall if i turn on my headlights, turn on the turn signals, and hit the brakes.

Thankfully, I recieved my new alternater from FedEx lastnight, and I'll be installing it this weekend along with rebuilding the ZS carb, and adjusting the valves to get rid of the annoying tapping... hopefully all this will go off without a hitch... /ubbthreads/images/graemlins/crazy.gif