Troubleshoot ignition switch issues.
What started out as strange electrical glitches– headlights not coming on, dash lights coming on, etc. is tied to the electrical ignition key switch (tumbler). Find in the thread linked below to diagnostic and the how-to to fix the key tumbler in early 70 series Volvos. A special thanks goes to Rob3 for finding the solution!
MVS Forum Member Rob3 asks:
Hello to all. This is my first post, so please be gentle. ;^)
My ’99 V70 has, what seems to be, a Temperature related Lighting problem. This car has about 90K Miles on it.
Once the temperature gets into the 40’s (Fahrenheit) or below, the Headlights, Dash Lights, Back-up Lights, Turn Signals, Electric Rear Defroster, Seat Belt Warning Lights, Mirror Heaters and possibly other items that I’m not aware of, will not come on immediately after starting the car. They will eventually come on.
The colder it is, the longer it takes for them to come on. It may take up to 5 or 6 minutes (so far) before they come on. Once they turn on, they work flawlessly for the rest of the trip.
Wiggling the Key Switch makes no difference. Driving through potholes makes no difference. Wetness makes no difference. Removing the Battery for 5 minutes makes no difference.
The High Beams / Exterior Courtesy Lights Switch will light the Headlights as long as it is held. Park Lights will work when selected, and will light the Dash Lights. The Radio and A/C System are working fine.
I suspect that some “Module” is malfunctioning until the Electricity fed through it heats it up enough to begin working. I hope I’m wrong.
Can anyone help? I’m really hoping that someone can check a Schematic and find the point(s) that are common for these Systems and can tell me physically where these points are.
Thanks in advance.
MVS Forum Member billofdurham replied:
Welcome to Matthew’s Volvo site, we are always gentle.
The only common thing I can work out is that the majority of the items that take time to work have relays in the central electrical unit (fuse box). However, other relays in there, eg the fuel pump relay, don’t appear to be affected.
All I can suggest at the moment is that you check/clean the earth (ground) point for the CEU and also check/clean the main battery terminals, not forgetting the end connected to the car body.
MVS Forum Member Rob3 added:
A Progress Report and a Question.
I obtained a Schematic. I traced the problem down to a matter of no Voltage is being sent to the Relay Coil during the Problem.
The last thing I’ve done is this: I tried turning the Key about 3 times from the Off position to the Run position without starting the Car. The Lights did not come on. I tried using a Blow Dryer and heated the Ignition Switch for about 1 minute before inserting the Key. The Lights came on immediately upon turning the Key.
I haven’t absolutely confirmed that the Key Switch is bad (I will), but I’m pretty confident that it is bad.
Does anyone know what is involved in fixing this? Any pointers are appreciated. I have no Service Manuals for this Car.
Thanks in advance.