1989 Pontiac Boneville, 3.8 fuel injection. When it is colder, the idle speed is dramatically higher than in the summer. The speed is about 1,500 rpms and takes a while to lower to 800. Also, the electric fan for the radiator is not working. When I turn on the a/c, it does come on. Wondering if the two problems are related. Bad temperature control sensor or something like that? Any help would be appreciated.

'88 Chrysler NY Landau 3.0 Prob. started w/ceiling read-out saying "improper voltage". Voltage was 10.56V. Then it said "engine temp high" It wasn't. Then all sorts of error messages. Then LED dash went blank - then on - then blank - then on etc., etc., etc.. Volt meter on dash showed low - then normal - then low - then normal,etc., etc., etc.. Headlights on - then off - then on (conserving the juice??). Headlight doors would not open - screwed them up/open. Computer diag. @ gas station = low voltage & lock-up solonoid bad. BS. Lock-up solonoid is working. SMEC controls voltage on this car. QUES: SMEC or alternator? Me thinks the computer but would like confirmation please. The mechanics in my area really suck. How do I know ? After $5,000 worth of work; including a new Jasper engine that leaks oil from the left head and valves are way out of adjustment (clickity clickity from day one); new rack & pinon and new front wheel hub assy's; all in the last 6 mo's @ 3 different shops believe me, I know. All the work was done by shoemakers. I can't get anybody to tell me what it IS.