Volvo 850 GLT - Electrical power loss while driving Topic is solved

jmcguire · Post by **jmcguire** » 04 Jan 2022, 17:28

My daughter was driving home from work last night and had a temporary total electrical power loss. The car went completely dark for about a second or 2 (headlights, dash lights, radio) then came back on its own.

I took the car out today to try to recreate the issue. I drove it around normally for about an hour and it was running perfectly. On the way home I drove it a little harder and found that if floored the gas pedal then let up on it, the power would go out as the rpm’s dropped. Gauges all dropped to the bottom and the radio shut off. About a second or two later everything came back on and I had to enter the radio code. (I also had a talk with my daughter about her driving habits)

Anybody know what could be causing this? Has to be something electrical and not mechanical… Car starts right up and idles smoothly. No dimming headlights when accelerator is pressed. Power does not cut out when revving engine in park or neutral.

This is a 1996 Volvo 850 GLT sedan with automatic transmission and just over 78,000 miles.

Post by **Chuck W** » 04 Jan 2022, 17:42

Sounds more like something is "loose", and excessive engine movement is causing the problem. (Based on your description)

Is the battery secured?

Engine mounts good? Grounds all tight and solid?

jmcguire · Post by **jmcguire** » 04 Jan 2022, 17:49

Chuck W wrote: ↑04 Jan 2022, 17:42 Sounds more like something is "loose", and excessive engine movement is causing the problem. (Based on your description)

Is the battery secured?

Engine mounts good? Grounds all tight and solid?

Checked the battery and the grounds. No corrosion and everything is tight. Upper torque mount was replaced at about 57,000 miles with poly. I’ll check the others tomorrow.

Post by **abscate** » 04 Jan 2022, 18:38

I would look at the battery feeds first, then the electrical part of the ignition switch if that’s original

Post by **erikv11** » 04 Jan 2022, 20:09

abscate wrote: ↑04 Jan 2022, 18:38 I would look at the battery feeds first, then the electrical part of the ignition switch if that’s original

aye and aye

Post by **Chuck W** » 04 Jan 2022, 21:39

jmcguire wrote: ↑04 Jan 2022, 17:49
Chuck W wrote: ↑04 Jan 2022, 17:42 Sounds more like something is "loose", and excessive engine movement is causing the problem. (Based on your description)

Is the battery secured?

Engine mounts good? Grounds all tight and solid?
Checked the battery and the grounds. No corrosion and everything is tight. Upper torque mount was replaced at about 57,000 miles with poly. I’ll check the others tomorrow.

Can you replicate it with a "wiggle" test? Any change while the car is idling when messing with the power/ground and other harnesses?

jmcguire · Post by **jmcguire** » 05 Jan 2022, 14:07

After checking all connections, grounds and fuses that I could, I went to the local pick-a-part and pulled the ignition switch from a ‘97. After swapping the ignition switch and taking it for a 30 minute test drive, it seems that the issue is solved. I’m going to order a new ignition switch and install it since I don’t fully trust the used one. Thanks for the help!

Post by **Eddystone** » 05 Jan 2022, 14:21

It does seem odd that it would be the ignition switch at only 78,000. Still sounds like a loose connection or maybe a connection that somewhat corrodes or a relay that needs to be reseated after many years. A bad ignition switch would certainly cut power as described, but why under sudden deceleration or acceleration. Keep us posted!

jmcguire · Post by **jmcguire** » 05 Jan 2022, 14:39

Eddystone wrote: ↑05 Jan 2022, 14:21 It does seem odd that it would be the ignition switch at only 78,000. Still sounds like a loose connection or maybe a connection that somewhat corrodes or a relay that needs to be reseated after many years. A bad ignition switch would certainly cut power as described, but why under sudden deceleration or acceleration. Keep us posted!

I found it odd too, but she does have a few other keys on her key ring and I noticed during the last test drive that the keychain does swing when accelerating like that. The new ignition switch has less key movement when in the run position than the original. If the issue resurfaces, I’ll be sure to let you know!

Post by **BEJinFbk** » 05 Jan 2022, 16:24

What DOESN’T make sense about that fix
is the radio losing power. Constant power
from the battery to the radio does not run
through or get otherwise interrupted by
the ignition switch.