ALT light bulb replacement

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   The 158 bulb is a wedge base. The 1445 is a bayonet base so the 1445 won't work. What's the electrical characteristic that differs between these two bulbs ? Are we looking for a replacement wedge bulb that is rated higher or lower in amp draw, or wattage ? 

The 158 is rated at 3.5 watts, 2 CP. The 1445 is rated at 1.87 watts but I can't find a listing for the CP. 

Here's what I can find in wedge base specs. From what I can tell these are rated at 12 volts.
158 3.5 Watts
161 5.0 Watts
168 4.0 Watts
194 3.0 Watts

I haven't found a wedge base bulb with a wattage rating of under 3.0 watts. I have to assume that the lower the wattage, the lower the CP and the lower current draw meaning a higher internal resistance. If all else fails try a #194 ??

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george w Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Joined: Jan/27/2013 Location: New Jersey Status: Offline Points: 2899	Post Options Post Reply Quote george w Report Post Thanks(0) Quote Reply Topic: ALT light bulb replacement Posted: Nov/27/2017 at 9:34pm
	The 158 bulb is a wedge base. The 1445 is a bayonet base so the 1445 won't work. What's the electrical characteristic that differs between these two bulbs ? Are we looking for a replacement wedge bulb that is rated higher or lower in amp draw, or wattage ? The 158 is rated at 3.5 watts, 2 CP. The 1445 is rated at 1.87 watts but I can't find a listing for the CP. Here's what I can find in wedge base specs. From what I can tell these are rated at 12 volts. 158 3.5 Watts 161 5.0 Watts 168 4.0 Watts 194 3.0 Watts I haven't found a wedge base bulb with a wattage rating of under 3.0 watts. I have to assume that the lower the wattage, the lower the CP and the lower current draw meaning a higher internal resistance. If all else fails try a #194 ??
	Long time AMC fan. Ambassador 343, AMX 390, Hornet 360, Spirit 304 and Javelin 390. All but javelin bought new.

billd Members Profile Send Private Message Find Members Posts Add to Buddy List Moderator Group Forum Administrator Joined: Jun/27/2007 Location: Iowa Status: Offline Points: 30894	Post Options Post Reply Quote billd Report Post Thanks(0) Quote Reply Posted: Dec/01/2017 at 7:54pm
	You may have seen my post on alternator/charging system tests - I have a post there that contains this tidbit: According to AMC, replace the original equipment #158 bulb with their service replacement, bulb number 1445. AMC deemed the 158 may be too sensitive. However, as you noted, there's a difference - and AMC also had a KIT that was bulb AND SOCKET. So, you need to find the correct socket as well. The technical service bulletin gives a kit number, bulb and socket.
	http://theamcpages.com http://antique-engines.com