Where is Ground Connection"B" ? Options

[kenshapiro2002]

As to check point 3 below...pin49A, the BLK/GRN/WH wire, only goes to the turn signal switch and the four way flasher switch. Others were saying that any item on the same ground circuit could be activating this flasher relay if they were not properly grounded...juice could be coming in through the ground?

P.S. Gave up for awhile on getting this damn relay out of it's socket...very stubborn little bugger.

Nice pic of the fuse. The side with one wire is the hot side. The side with the 2 lugs is the protected (by fuse 9) side. This is the side to measure. Here we'd be looking for any jumping of the voltage caused by other loads.

I think the flasher relay is a little metal box. The wires should be in either a connector or somehow attached to the plate. I've never taken one apart so I have no experience with dissassembly.

If there is a connector, we can still work with that. What we wand to do is this:

1) Check the voltage into the circuit on pin 49. This should be stable for all loading (lights, radio, wipers, etc)

2) Check the ground wire resistance on Pin 31. This should be very low resistance. Like 0 to 1 ohms.

3) Find some other electrical path on pin 49a that causes the load that causes the chatter.

[kenshapiro2002]

Got it out...off to test the hot and ground. I'm starting to understand this crap.

[kenshapiro2002]

OK...pin 31 (ground) is excellent. Pin 49 is getting 12 volts and it's not fluctuating with the different loads. This seems wrong though...as soon as I turn on the ignition, the flasher relay is getting 12 volts, but it's not making any sound. I guess it's quiet until it gets a signal from the flashers through one of the other pins?

[kenshapiro2002]

Yeah...after looking at the schematic, I think it's normal for the red lead to be "hot" as soon as the ignition is turned on. Seems the flasher relay is good as is its ground and power source. My rookie guess is till that something else is wrong and is powering up the relay through the ground wire.

Significant evidence seems to me to be:

When I took delivery of the car, the problem did not exist. The brake light switch on the brake pedal was so far out of adjustment that no brake lights went on. I fixed that. Unplugging it does not eleviate my current problem. The handbrake switch was screwed up and did not work either. I freed that up now and it works. There was no bulb in the multi gauge for the handbrake light / brake failure. A PO had[i] to have removed it because of some electrical glitch that had it on all the time.

When I took delivery of the car, the turn signal indicators were screwy. One of them would flash correctly (can't remember which one), and the other would start to flash on its correct side, and then both arrows would start to flash at the same time.

OK...pin 31 (ground) is excellent. Pin 49 is getting 12 volts and it's not fluctuating with the different loads. This seems wrong though...as soon as I turn on the ignition, the flasher relay is getting 12 volts, but it's not making any sound. I guess it's quiet until it gets a signal from the flashers through one of the other pins?

[SirAndy]

would start to flash on its correct side, and then both arrows would start to flash at the same time

My memory on that is a bit hazy, but i have seen a lot of 914s do that. It's either a bad switch or a ground problem.

I fixed it on my car by adding an additional ground to those bulbs, but that's a bandaid.
I think they are supposed to be grounded at one of the switches.


But like i said, it's been years since i worked on this the last time. Maybe it's time to whip out the good 'ole search function because i also vaguely remember a solution posted here a while ago.

(IMG:style_emoticons/default/chowtime.gif) Andy

[kenshapiro2002]

Never had any luck with the search function on this site...not sure why.

would start to flash on its correct side, and then both arrows would start to flash at the same time

My memory on that is a bit hazy, but i have seen a lot of 914s do that. It's either a bad switch or a ground problem.

I fixed it on my car by adding an additional ground to those bulbs, but that's a bandaid.
I think they are supposed to be grounded at one of the switches.


But like i said, it's been years since i worked on this the last time. Maybe it's time to whip out the good 'ole search function because i also vaguely remember a solution posted here a while ago.

(IMG:style_emoticons/default/chowtime.gif) Andy

[kenshapiro2002]

Did some searching and found that others have hd simiar problems with many different solutions. Found this:

>I noticed the other night my turn signal relay just started clicking when I was out driving around. My turn signals still work but the relay continues to click.

Do any brake master cylinder work on the car lately?
Is your brake fluid level getting low?
The relay circuit includes the brake warning system.

Two weeks ago I replaced the master cylinder in my 914. First time I fired it up with the new MC, the turn signal relay started clicking none stop[the relay drives every light that flashes] . The brake warning light would flash occasionally, but the relay kept clicking constantly.

Drove me crazy for two weeks. Bled the brakes a few times, but that did not satisfy the brake warning system. The brakes felt & performed fine.

Problem solved:
The new master cylinder came with a single wire sensor, the old MC had a 2-wire sensor(Gnd & signal). So I installed the old sensor on the new MC when I first installed it. It turns out the new sensor's plunger length is shorter than the old sensor's, by about 1/8". So I shortened the old sensor's plunger to match the length of the new sensor's, and now no more flashing brake warning light, and no more signal relay clicking.

Moral of this tale?
Since you probably don't have a mis-matched master cylinder to brake warning sensor,
your brake fluid warning system may be about to trigger.

would start to flash on its correct side, and then both arrows would start to flash at the same time

My memory on that is a bit hazy, but i have seen a lot of 914s do that. It's either a bad switch or a ground problem.

I fixed it on my car by adding an additional ground to those bulbs, but that's a bandaid.
I think they are supposed to be grounded at one of the switches.


But like i said, it's been years since i worked on this the last time. Maybe it's time to whip out the good 'ole search function because i also vaguely remember a solution posted here a while ago.

(IMG:style_emoticons/default/chowtime.gif) Andy

[Spoke]

When I took delivery of the car, the turn signal indicators were screwy. One of them would flash correctly (can't remember which one), and the other would start to flash on its correct side, and then both arrows would start to flash at the same time.

When both flashed together, were they 1/2 brightness? This seems to be a common failure of the flasher relay. Look at the schematic and imagine what happens if the center connection of the indicator lights doesn't connect to pin 49 as the schematic shows. If the relay on pin K doesn't close when the turn signals are on, both lamps will light and will split the voltage 6v across each lamp.

Like Andy mentioned, if the center connection of the indicator lamps is disconnected from pin K and connected to ground, then each indicator will flash as desired. The bulbs will have to be reversed in their sockets since the right indicator is connected to the left bulbs and the left indicator to the right bulbs.

My rookie guess is till that something else is wrong and is powering up the relay through the ground wire.

You can check this in 2 ways. Disconnect the flasher relay and measure resistance (ohms) from the brown wire to chassis. This measurement should show less than 1 ohm.

Second way is to measure voltage on the brown wire to chassis when power is applied to loads like brake lights, radio, wipers, etc. This measurement should show zero voltage if the wire is ok.

Do this test: Remove the flasher relay and measure resistance (ohms) to chassis on the wire connected to pin 49a. With 4-way flashers and turn signals off, you should measure infinite ohms (no deflection on an analog needle) or the same reading on a digital multimeter when measuring ohms and the probes are not touching anything.

If you measure resistance, something is pulling down on the relay and could be causing it to chatter.

[kenshapiro2002]

On this part should I be powered up and trying items other than the 4 ways and flashers?


[/u][/i]Do this test: Remove the flasher relay and measure resistance (ohms) to chassis on the wire connected to pin 49a. With 4-way flashers and turn signals off, you should measure infinite ohms (no deflection on an analog needle) or the same reading on a digital multimeter when measuring ohms and the probes are not touching anything.

If you measure resistance, something is pulling down on the relay and could be causing it to chatter.
[/quote]

[Spoke]

On this part should I be powered up and trying items other than the 4 ways and flashers?

]Do this test: Remove the flasher relay and measure resistance (ohms) to chassis on the wire connected to pin 49a. With 4-way flashers and turn signals off, you should measure infinite ohms (no deflection on an analog needle) or the same reading on a digital multimeter when measuring ohms and the probes are not touching anything.

If you measure resistance, something is pulling down on the relay and could be causing it to chatter.

No power on this test. You are looking for something that is an electrical load on the flasher. The electrical load may present itself as a resistance to ground.

Something is loading the flasher such that it tries to turn on all the time. There may be a path of resistance from pin 49a to ground that we're looking for.

In general, the flasher is a simple circuit. It only has 3 real pins (discounting pin K):
o Power pin 49
o Ground pin 31
o Output pin 49a

If power pin 49 is ok (no wild voltage swings during operation) and ground pin 31 is ok (no noticeable voltage on the ground pin during operation), then that leaves just output pin 49a.

[kenshapiro2002]

You can check this in 2 ways. Disconnect the flasher relay and measure resistance (ohms) from the brown wire to chassis. This measurement should show less than 1 ohm. PERFECT

Second way is to measure voltage on the brown wire to chassis when power is applied to loads like brake lights, radio, wipers, etc. This measurement should show zero voltage if the wire is ok. PERFECT

Do this test: Remove the flasher relay and measure resistance (ohms) to chassis on the wire connected to pin 49a. With 4-way flashers and turn signals off, you should measure infinite ohms (no deflection on an analog needle) or the same reading on a digital multimeter when measuring ohms and the probes are not touching anything. [b]PERFECT

If you measure resistance, something is pulling down on the relay and could be causing it to chatter.
[/quote]

[kenshapiro2002]

So, if the flasher relay passes all of these tests. Where do I go from here? Since even just using that circuit the way it's supposed to be used , like using the 4 way flashers, causes the relay to go crazy, doesn't that indicate that the relay itself is bad? Can there be another explanation? If there's no load going into that relay at all and the using the flashers or 4 way flashers causes it to go crazy, what else could be the explanation other than a bad relay?

You can check this in 2 ways. Disconnect the flasher relay and measure resistance (ohms) from the brown wire to chassis. This measurement should show less than 1 ohm. PERFECT

Second way is to measure voltage on the brown wire to chassis when power is applied to loads like brake lights, radio, wipers, etc. This measurement should show zero voltage if the wire is ok. PERFECT

Do this test: Remove the flasher relay and measure resistance (ohms) to chassis on the wire connected to pin 49a. With 4-way flashers and turn signals off, you should measure infinite ohms (no deflection on an analog needle) or the same reading on a digital multimeter when measuring ohms and the probes are not touching anything. [b]PERFECT

If you measure resistance, something is pulling down on the relay and could be causing it to chatter.

[kenshapiro2002]

OK...decided to run every possible test on the relay itself for resistance. Here's what I found:

49 - K = ∞
49A - K = ∞
31 - K = ∞

49 - 49A = 300
49A - 31 = 1900
49 - 31 = 1800

[FourBlades]

I'd say buy a new relay or try one known to be good from a friend's car. That
will either solve the problem or eliminate the relay as a possibility. You could
also try tracing all the wires involved and look for shorts, cracks in the insulation,
bad connections, etc.

You could also try taking out all the fuses except #9 and see if the problem still
exists. If it still exists, the problem is in this circuit. If the problem goes away,
try adding fuses back one by one. When it comes back, then there must be
some interconnection in the circuits that is causing the problem. Having hard
information like this is very helpful in finding the problem.

I am no expert on 914 wiring, and this advice may not help, but I know from
engineering that you need to isolate the problem, and definitively rule things out
one by one. Often times the hardest bugs to track down were ones that people
thought "for sure" they had ruled out. Usually it turned out that they "assumed"
that something was good instead of "testing" it for sure. This caused them to
look at every other possibility except the one they "assumed" was ok.

I need to debug my blue car here soon and I am sure I will have similar
issues.

Good luck.

John

[kenshapiro2002]

Thanks.

I'd say buy a new relay or try one known to be good from a friend's car. That
will either solve the problem or eliminate the relay as a possibility. You could
also try tracing all the wires involved and look for shorts, cracks in the insulation,
bad connections, etc.

You could also try taking out all the fuses except #9 and see if the problem still
exists. If it still exists, the problem is in this circuit. If the problem goes away,
try adding fuses back one by one. When it comes back, then there must be
some interconnection in the circuits that is causing the problem. Having hard
information like this is very helpful in finding the problem.

I am no expert on 914 wiring, and this advice may not help, but I know from
engineering that you need to isolate the problem, and definitively rule things out
one by one. Often times the hardest bugs to track down were ones that people
thought "for sure" they had ruled out. Usually it turned out that they "assumed"
that something was good instead of "testing" it for sure. This caused them to
look at every other possibility except the one they "assumed" was ok.

I need to debug my blue car here soon and I am sure I will have similar
issues.

Good luck.

John

[Spoke]

The resistances of the relay look good. I don't think the relay is at fault.

Sorry for asking for all the measurements. Troubleshooting from afar is pretty difficult. We're trying to isolate the issue. There is (usually) one thing wrong but it's hard to find. Experiments and measurements will help isolate the issue.

In previous tests, what was the resistance of the ground wire (brown) to chassis that you measured before?

Have you tried this test: remove the 49a wire from the flasher relay and turn the power on. This should remove all loads from the flasher and it should not chatter. This will also confirm your 12V power and ground connection. No lights will flash, but then again we're just trying to isolate the issue.

I have another test in mind but it's really radical. I'll dump this one on you later if the issue still exists.

[kenshapiro2002]

Ground wire (31) has always shown zero.

Just eliminated 49A and the problem still exists. No lights flashed but the other power sources still got the relay to chattering.

The resistances of the relay look good. I don't think the relay is at fault.

Sorry for asking for all the measurements. Troubleshooting from afar is pretty difficult. We're trying to isolate the issue. There is (usually) one thing wrong but it's hard to find. Experiments and measurements will help isolate the issue.

In previous tests, what was the resistance of the ground wire (brown) to chassis that you measured before?

Have you tried this test: remove the 49a wire from the flasher relay and turn the power on. This should remove all loads from the flasher and it should not chatter. This will also confirm your 12V power and ground connection. No lights will flash, but then again we're just trying to isolate the issue.

I have another test in mind but it's really radical. I'll dump this one on you later if the issue still exists.

[silverteener]

I can't help you with your problem but I see Spoke is here and he helped me fix my problem I was working on for Months. he was very patient and really knows how to trace! Good luck and don't give up.

[kenshapiro2002]

I read through your ordeal last night and it gave me the boost I needed not to go out and beat up an old lady...saw that you were pretty lost (like I am), but stuck it out and conquered it through these good friends, like Spoke and the others.

I can't help you with your problem but I see Spoke is here and he helped me fix my problem I was working on for Months. he was very patient and really knows how to trace! Good luck and don't give up.

[Spoke]

Ground wire (31) has always shown zero.

Just eliminated 49A and the problem still exists. No lights flashed but the other power sources still got the relay to chattering.

OK. This is good news. This eliminates any of the loads (master cylinder switch, ebrake switch, etc.) from causing the problem. We're narrowing down the possible issues. With 49a removed, you are just connected to power (49), ground (31), and the indicator lamps (K).

Try to remove K at the same time 49a is removed. This leaves just power (49) and ground (31) connected. If the chatter continues with K and 49a removed, then just power and ground are connected.