Is it possible for turn signals to fail intermittently?

Dear Car Talk

Dear Car Talk | Nov 29, 2011

Dear Tom and Ray:

I currently have the misfortune of needing to drive a beat-up 1995 Volvo 850, which I share with my husband, who fancies himself an expert on cars. As a general rule, I try not to argue with him on any subject involving cars (or, for that matter, about anything else, since reason and logic are not his strong points). Alas, during this past week, something about this wretched Volvo went wrong, forcing me to open a dialogue with Mr. Know-It-All-About-Cars. Out of the blue, the blinkers (the right and left signals) quit working. Once in a while, the signals work, but most of the time they don't. My husband stubbornly refuses to believe that they don't work. He claims that they are working just fine for him, ergo I must be doing something to keep them from working! He says he won't look into fixing it unless he experiences the problem himself. Is it unusual for signals to work intermittently? Can you please help me, ASAP?

-- Terry

RAY: Gee, this guy sounds like a real gem, Terry. How do you keep the other girls away from him?

TOM: The blinkers absolutely can fail intermittently. A lot of electronic parts fail that way. There are three things that could be at fault here.

RAY: The cheapest, and easiest to fix, is the hazard switch. The hazard switch in this car contains a relay, which also is used by the directional switch. If the relay is sticky, that can cause the directionals to fail sometimes.

TOM: It would cause your hazard lights to fail, too. So next time this happens, try turning on the hazard lights to see if they're working normally. If not, buy a new hazard-light switch, gently pry the old one out of its hole in the dashboard, plug in the new one and you're done. That'll cost you about $50.

RAY: The second possibility is that the directional switch itself -- the stalk that sticks out of the steering column -- is failing. That's also pretty easy to fix, since most Volvos of that era used a dedicated directional stalk, rather than the multipurpose switches (lights, high beams, etc.) that you see on lots of other cars. If that's the part that's dying, you're looking at spending around $100.

TOM: And if it's neither of those, then unfortunately the problem probably is in the ignition switch. Volvo 850s are famous for worn-out ignition switches.

RAY: What happens is that when you start the car, you push the key past the "run" position to the "start" position until it cranks and starts. Then you let go of the key, and it's supposed to spring back to the "run" position. But on these cars, the key often will not spring back all the way. And since much of the car's electrical equipment runs through the ignition switch, a bad switch can lead to all kinds of electrical shenanigans.

TOM: You can test that theory by lightly jiggling the key in the ignition next time the blinkers fail. If you can get them to work that way, you may have found the problem. But that's an expensive part. It'll probably run you about $300.

RAY: And if none of those ideas works, you'll have to divorce your husband and use the settlement to buy a new car, Terry. That'll cost HIM $100,000. Remind him of that if he keeps refusing to help you.

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