Ever have an intermittent problemith a relay?

Michael C Henry · #1 (**permalink**) 06-03-2011, 06:24 PM

A couple of weeks ago I drove the car to the doctors office, The car died just in front of the parking spot. I lost electrical power. All I had was the dimm ignition indicator lamp. I found that when I urned on the head ligths momentarilly, the ignition indicator lamp is bright, fuel pump is running and it will start. Thought I had it fixed when I reconnected the wires on the back of the ignition key switch.
Memorial Day I Had evrything ready for a ride. I turned on the ignition ran the fuel pump to fill up carbs, and turned off the ignition and waited for my wife to appear. Once she opened the garage door I tried to start the engine. I turned on the ignition key switch and I only had the dimm indicator lamp,no fuel pump, and no start. This timeI found if I turned on the head ligths even momentarilly, everything started working. I'd turn off the headligths and turn off and back on the ignition key switch and I'd only get that dimm indicator lamp. I did this repeatidy,a constant thing that I can recreate time after time and I could actually find the bad part. I removed the steering wheel and drivers seat. Then it starts working constantly. I haven't done anything that I could take credit for. I'm using a bank of four relays . I know I have not done anything that I could take credit for. Do relays just fix them selves?

FWB · #2 (**permalink**) 06-03-2011, 06:44 PM

check the battery and the terminals. a loose terminal can do that, when you load it it'll arc and weld itself temporarily. likewise a bad headlamp switch or ignition switch could also do it.

Michael C Henry · #3 (**permalink**) 06-04-2011, 12:35 AM

If there is a loose conection I haven't found it yet. When it was acting up , I left the ignition turned on with the dimm indicator lamp lit and didn't see it flicker get bright or anything else when I tested the battery, ground, and master switch connections. I even had the fuel pump turned off so I might be able to hear a click of a solinoid if I did cause anything to change.

PDUB · #4 (**permalink**) 06-04-2011, 01:02 AM

Sure, relays can fail, like anything else... contacts can become corroded or burned, etc. They can even weld themselves together

.

As mentioned above, sounds like you may have a loose connection somewhere, or the ignition switch, depending on what it is could be the culprit, too.

If it happens again, you could try swapping out the relay in question.

________________

Michael C Henry · #5 (**permalink**) 06-04-2011, 10:41 AM

I checked the major cabels, all tight. I think it's something later down the circuit. 4 ways are wired around first master switch for emergencies, they worked great while ignition indicator lamp was still dimm. Head lamps are controled off ignition key switch and they're(even momentary) draw is what was causing everything to reconnect. The car has a seperate push button for starter, it wouldn't do anything when the indicator lamp was dimm. As I remember that is the original key switch that was in the car when I bought it in 99. If I were to buy another key switch, would it be built as well as the one I'm replacing. Thekey ignition has three terminals and three positions accessory-off- and ignition and accessory. Lately they have made it an art to cheapen everything asfar as possible some time too much.

PDUB · #6 (**permalink**) 06-04-2011, 10:25 PM

Can't comment on that, but with what you said in this last post, I'd be suspicious of the ignition switch, since all of the issues seem to lead back to it.

Did you try wiggling the ignition and/or cycling the ignition switch when it happened before? If not, you might try to recreate the problem and see if that will have an effect on it.

Michael C Henry · #7 (**permalink**) 06-04-2011, 10:32 PM

I drove the car on a trip from Tacoma to Sumner. On 512 My SWvoltage gage went to 15.5+ volts for the whole trip at about 3,ooo rpm , about 20 minutes. I stalled the engine at a street light in Sumner everything went dead again. I was prepared and turrned on the headlights. The engine restarted and we were off. Now I notice that the voltage is now at about 14 volts. We went to the resturant and drove home with the voltage at 14 volts and everything operating correctly. I didn't notice the voltage before. Could the voltage regulator be the problem? I had a problem with the original voltage regulator a few years back. I bought a new voltage regulator at Baxter. That voltage regulator broke emediatly and Baxter replaced that voltage regulator with the one I now have. Are there better regulator available?

Dangerous Doug · #8 (**permalink**) 06-04-2011, 11:45 PM

Relays can act intermittently. My headlight dimmer relay, a Mehle (sp?), was intermittent. This was a known problem that ERA had identified, so solving it was relatively easy. It was a relay used in Volkswagens, so I went to airheads.com and found what they use for a replacement for the Mehle part. Worked great ever since I replaced it.

I ended up taking apart the original Mehle relay, and I could see why it failed: the mechanism relied upon a small blade bending back and forth to flip a mechanical switch. the blade did not bend reliably.

Diagnosing it was easy, as all I had to do was repeatedly hit the dimmer switch and watch the headlights (normal, bright, then off...OFF?!!!), listening to the solenoid click back and forth.

Finding the correct replacement was an entirely different problem.

Good luck.

DD