1992 Volvo 740 Intermittant variable electrical system fail

ICYE

MEMBER
1992 VOLVO 740
4 CYL
2WD
AUTOMATIC
85,000 MILES

Sometimes all is well. Then start engine. ABS lite shows, windows won't work, and most important cannot shift from park -frozen shifter.
Cure: Turn off then go to ignition or electrical 'on' position without cranking engine. Then put in neutral and start engine. If battery is low ABS dummy lite stays on, dead windows, and/or no headlites.

Full charge of newish battery helps but doesn't solve anything.

Alternator volt test good with all electial crap on. Battery tests good when charged. Battery cables are tite.
Engine runs fine. Doesn't quite or stumble.

Seems to not really be a charging problem.
seems to be a hard to locate drain - bad part.

Hotter and colder weather may make this act up more.

5 shops have been clueless including Dealer in Medford, Or. Verdict is always that there is no drain but battery needs some charge.

1 Reply

DOCFIXIT

MECHANIC
18,828 POSTS

Hi all things that fail to function need power from ignition switch #50 term pink wire. Sometimes key does not make that contact possibily because of high resistence. So if batt low cannot complet circuit.
As for possible battery drain with all doors closed. Ect hook up Amp meter in series with Neg battery cable. Let system relays stabalize then meter should not read over.5 milliamps. If more start pulling fuses till it comes down that is circuit that is draining batt.
Hope this helps
Thanks for donate